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AT    LOS  ANGELES 


GIFT  OF 

Los  Angeles 
Chamber  of  Commerce 


/; 


CLAYS 


OF 


ECONOMIC   VALUE 


IN 


NORTH   DAKOTA 


K.    J.    BABCOCIS:, 

Professor  of  Chemistry  and  Geology,  University  of  North  Dal<ota. 


ISSUED  15  V 

H.  T.  HELGESEN, 

State  Commissioner  of  Ag^riculture  and  Labor. 


BISMARCK,  x\.  D.: 

TRIBUNE,   STATE   PRINTERS   AND   BINDERS. 
1892. 


3530-7 


NORTH  DAKOTA  CLAYS. 


Two  years  ago,  Prof.  E.  J.  Babcock,  of  the  State  University,  did 
some  valuable  work  for  the  benefit  of  the  State,  which  was  pre- 
sented under  the  title,  "Coal  and  Sugar  Beets,"  in  the  first  biennial 
report  of  this  office.  Several  months  ago  he  informed  the  Com- 
missioner that  he  had  been  engaged  for  some  time  in  an  investi- 
gation of  the  clays  of  the  State,  and  that  if  a  report  of  his  work 
was  desired  for  this  department  he  would  prepare  one  for  publi- 
cation, in  a  manner  similar  to  that  in  which  his  papers  on  coal  and 
sugar  beets  had  been  published.  He  was  assured  that  such  a 
paper  would  be  appreciated  by  the  present  Commissioner,  and,  if 
apjjroved  by  the  governor,  as  provided  in  Chapter  99  of  the  Laws 
of  189'1,  would  be  published  sef)arately  as  well  as  incorporated  in 
the  report  of  this  office.  The  following  valuable  paper  is  the 
result  of  his  work,  and  for  which  he  is  entitled  to  the  gratitude 
of  the  State. 

H.  T.  Helgesen, 
Commissioner  of  Agriculture  and  Labor. 

UNIVERSITY  OF  NORTH  DAKOTA,      ) 
Grand  Forks,  N.  D.,  Nov.  1,  1892.  { 
Hon.  H.  T.  Helgesen,  Commissioner  of  Agriculture  and  Labor  for 
North  Dakota: 

Sir: — I  herewith  place  in  your  hands  for  publication,  if  it  shall 
seem  to  you  worthy,  a  report  on  the  clays  of  North  Dakota.  There  is 
no  appropriation  for  work  of  this  character,  but  having  become  much 
interested  in  the  clays  of  the  State,  I  determined  to  make  a  prelimi- 
nary investigation  of  the  subject,  at  my  own  expense  if  necessary. 
This  has  been  done  without  the  expectation  of  personal  remuner- 
ation. I  regret  that  lack  of  time  and  means  has  rendered  it  im- 
possible to  make  these  investigations  more  thorough  and  extended, 
and  in  many  ways  more  satisfactory.  It  is  hoped,  however,  that 
what  has  been  done  may  help  in  the  development  of  the  natural 
resources  of  North  Dakota.  I  have  the  honor  of  presenting  to 
the  State  the  result  of  my  investigations. 

Very  respectfully, 

E.  J.  Babcock, 
Department  of  Chemistry  and  Geology, 

State  University  of  North  Dakota. 


.'J!Hn.'^*> 


CLAYS  OF  ECONOMIC  VALUE  IN  NORTH  DAKOTA. 


The  object  of  the  following  pages  is  to  call  attention,  in  a 
simple  way,  to  some  of  the  clays  of  North  Dakota.  So  far,  prac- 
tically nothing  has  been  done  toward  the  utilization  of  the  clay, 
excepting  the  manufacture  of  common  brick  in  a  few  localities. 
It  is  with  the  hope  of  making  known  the  value  of  some  of  the 
clays  of  the  State  that  this  little  report  is  published. 

In  order  to  get  a  better  idea  of  the  clays  of  our  own  State,  the 
local  descriptions  will  be  preceded  by  a  few  general  statements  in 
regard  to  the  source  and  distribution  of  other  clays  and  the  com- 
position and  characteristics  required  for  various  uses. 

ORIGIN  AND  DISTRIBUTION. 

The  geographical  distribution  of  clays  is  very  extensive,  yet 
this  is  true  only  of  material  adapted  for  the  manufacture  of  com- 
mon brick  and  coarse  products.  Deposits  of  clay  fit  for  the  finer 
uses  are  by  no  means  common. 

The  geological  horizon  of  clays  suited  to  different  uses  varies 
"Widely  from  the  earliest  to  the  latest  formations.  Especially  is 
this  true  with  reference  to  the  clays  used  for  the  manufacture  of 
COMMON  BRICK  and  other  architectural  material.  Coarse  clays 
suited  for  these  purposes  are  frequently  found  in  drift-covered 
districts  where  the  underlying  deposits  are  free  from  sand, 
pebbles  and  excess  of  limestone.  This  is  how  some  of  the  brick 
clay  in  Northern  Minnesota  and  Dakota  occurs.  This  material  is 
also  often  found  as  lake  and  river  deposits  which  have  been 
formed  by  the  disintegration  of  surrounding  or  distant  gneissic  or 
feldspatic  rock  or  from  shale.  It  can  readily  be  seen  that  clays  of 
such  origin  are  not  likely  to  be  of  hiszh  grade  on  account  of  con- 
tamination by  objectionable  foreign  matter. 

A  better  grade  of  coarse  clay  is  often  found  with  the  fine  clays 
of  the  Cretaceous  and  Tertiary  formations.  From  this  some  ex- 
cellent brick,  terra  cotta,  and  drain  pipes  may  be  made.  Some  of 
the  coarse  clays  of  central  and  western  North  Dakota  are  of  this 
kind  and  will  doubtless  prove  their  worth.  It  would  naturally  be  in- 
ferred that  material  so  different  in  its  origin  varies  also  in  its  com- 
position and  characteristics  and  so  produces  articles  of  widely  dif- 
ferent values.  The  essentials  in  every  case  are  a  sufficient  pro- 
portion of  true  clay  basis  or  kaolin  element  to  produce  a  plastic, 
workable  body,  freedom  from  pebbles  and  from  an  excess  of  sand 
and  fusible  material.  Variety  in  the  color  of  brick  generally  re- 
sults from  varying  proportions  of  iron  and  the  intensity  of  the 
heat  to  which  the    brick   is  exposed.     Hard,  dense,  semi-vitreous 


brick  result  usually  from  clay  with  much  fluxing  material,  such  as 
the  alkalies  and  iron. 

Fire  clay  is  a  clay  sufficiently  refractory  to  withstand  extremely 
high  temperatures  without  disintegration  or  vitrification.  Such 
clays  are  extensively  used  for  the  manufacture  of  linings  for  furn- 
aces and  fire  places,  in  gasworks  and  potteries,  for  brick  and  other 
architectural  material  that  is  liable  to  be  subjected  to  great  heat. 
For  such  purposes  the  clay  must  be  very  free  from  the  fluxing 
constituents,  iron  and  the  alkalies.  Good  fire  clay  is  not  very 
common.  It  is  found  and  used  extensively  in  parts  of  England 
and  in  some  localities  on  the  European  continent.  In  America  it 
is  found  in  New  Jersey,  Missouri,  and  some  of  the  other  states. 
Doubtless  an  excellent  material  exists  in  North  Dakota,  as  will  be 
seen  from  succeeding  pages. 

As  to  the  geolosry,  it  may  be  said  that  most  of  the  fire  clays  are 
found  in  the  under  clay  of  the  coal  measures  and  in  the  Cretaceous 
and  Tertiary  deposits.  They  often  underlie  the  lignite  coal  beds. 
It  is  probable  that  the  fire  clays  of  North  Dakota  were  part  or  all 
under  the  lignite,  (probably  in  the  Laramie  group),  although  in 
some  localities,  as  near  Dickinson,  there  is  no  evidence  of 
coal  having  been  over  the  clay.  This,  however,  may  have  been 
the  case,  the  lignite  having  been  removed  from  over  the  clay  in 
certain  spots  by  action  of  water  during  the  great  erosion  to  which 
these  places  have  been  subject. 

The  term  pottek's  clay  is  very  wide  in  its  signification  as  it 
may  mean  any  plastic  clay  from  the  finest  porcelain  and  dish  clay 
to  thai,  used  for  the  manufacture  of  coarse  jugs  and  jars.  It  is 
evident  that  potter's  clay  fit  for  a  good  white  earthenware,  as  well 
as  that  of  lower  grade  for  jugs,  jars  and  the  like,  exists  in  North 
Dakota,  We  shall  here  consider  particularly  the  geology  of  the 
finer  clays  for  earthenware,  etc.  While  clays  fit  for  common  brick 
and  drain  pipes,  tiles  and  fine  terra  cotta,  and  even  yellow  dish 
ware  are  quite  widely  distributed,  fine  fire  clays  and  white  earthen- 
ware and  porcelain  clays  are  by  no  means  common.  Clays  fitted 
for  some  of  the  finer  purposes  just  mentioned  are  found  and  used 
principally  in  China,  in  central  Europe,  in  England  and  in 
the  United  States  in  New  Jersey,  Missouri  and  one  or  two  other 
localities. 

Cliina  clay,  also  known  as  Kaolin,  porcelain  clay,  etc.,  is  plenti- 
ful in  certain  localities  in  China.  Material  used  for  the  same  pur- 
pose is  also  found  in  parts  of  Germany  and  France.  In  England 
a  similar  clay,  known  as  Cornish  clay  from  Cornwall  and  Devon,  is 
the  basis  of  the  great  pottery  and  porcelain  industry  of  Stafford- 
shire, England. 

Most  of  the  clays  used  for  the  production  of  fine  earthenware 
and  the  better  whiteware  are  probably  derived  from  the  Cretaceous 
and  Carboniferous  formations,  and  the  most  extensively  worked 
deposits  of  this  kind  in  the  United  States  are  those  of  New  Jersey. 


The  clay  from  this  State  forms  the  basis  of  a  great  industry  cen- 
tering at  Trenton.  The  ware  produced  is  of  excellent  quality, 
and  the  clay  used  is  that  of  the  Cretaceous. 

While  potter's  clay  is  found  to  exist  in  several  regions  where 
not  particulai'ly  mentioned,  and  will  doubtless  be  found  in  other 
localities,  it  is  very  certain  that  the  finest  clays,  especially  those 
fit  for  porcelain,  will  continue  rare. 

The  clays  of  North  Dakota,  which,  from  this  report,  are  shown 
to  be  suited  to  the  production  of  finer  grades  of  whiteware,  are 
found  about  Dickinson,  and  are  jDrobably  in  the  Laramie  de- 
posits. The  best  clays  in  this  locality  occur  in  elevations  from 
150  to  200  feet  above  the  surrounding  valleys.  These  clay  knolls 
have  escaped  much  of  the  erosion  to  which  the  surrounding 
country  has  been  subject.  If  these  deposits  ever  extensively  cov- 
ered the  plain  far  east  of  Dickinson,  they  have  probably  been 
mostly  or  entirely  removed  by  the  longer  action  of  the  receding 
post-glacial  waters  as  they  narrowed  to  the  jjresent  basin  of  the 
Missouri  river.  The  ultimate  source  of  these  deposits  can  only  be 
conjectured,  but  when  we  remember  the  ease  with  which  fine 
sediment  in  water  is  transported  to  great  distances  from  its  origi- 
nal home,  it  does  not  seem  impossible  that  the  parent  rock,  whose 
disintegration  formed  the  basis  of  this  clay,  may  have  been  from 
the  feldspatic  rocks  occurring  to  the  west  and  northwest  along  the 
flank  of  the  Rocky  mountains. 

GEOLOGICAL  SUMMARY  OF   NORTH    DAKOTA  CLAYS. 


Post-Glacial  .  .  (  Yellow  and  blue  brick  clavs  of  the  Red  River 


Post  Tertiary — -j  •]      Valley;  probably   largely  washed    from  the 

Glacial (      adjoining  Cretaceous. 

Tertiary —  ('Plastic   Clays.     White    earthenware    and    fire 

'  I       claj'S  and  coal  of  Dickinson.     (Leaf  prints 

Laramie -(       etc.,  about  Dickinson,  probably  Laramie.) 

I  Clay  and   coal   at  Minot  and  at  Plenty  Mine, 

(^     Mercer  county,  probably  Laramie,  also. 

Cretaceous —  fThe  upper  non-fossiliferous  shales  about  Park  river,  Langdon,  etc., 

J       are   probably   Cretaceous    (Fort   Pierre),  as  well    as  the   under 

)       fossiliferous  and  hydraulic  cement  marl  of  the  Pembina  Moun- 

^^     tain  district. 

CHARACTERISTICS  AND  COMPOSITION. 

All  varieties  of  clay  originate  from  the  disintegration  of  felds- 
patic rock.  The  parent  rock,  subject  to  the  action  of  weather  and 
water,  and  finally  to  chemical  agencies,  is  broken,  ground  and 
separated  into  sand  and  clay.  The  harder  pure  quartz  of  the 
rock  remains  in  coarser  grains  as  sand  and  the  softer  feldspar,  by 
the  further  wearing  and  chemical  action,  is  reduced  to  an  impal- 
pable state  and  finally  deposited  as  a  bed  of  clay.     Clays  naturally 


partake  of  the  character  of  the  parent  rock.  For  example,  a  rock 
containing  much  iron  or  alkaline  matter,  would  be  likely  to  form 
a  clay  containing  a  considerable  proportion  of  these  constituents, 
while  a  rock  quite  free  from  such  ingredients,  would,  unless  con- 
taminated by  foreign  matter,  produce  a  comparatively  pure  clay. 
Impurities  are  often  added  to  clays  during  the  time  of  transpor- 
tation and  deposition.  After  deposition  the  character  of  the  clay 
is  often  if  not  always  subject  to  a  modification  corresponding  to 
the  make-up  of  the  superimposed  material.  Water  percolating 
through  an  overlying  deposition  is  almost  sure  to  find  some  solu- 
ble constituent  such  as  lime,  iron,  or  alkalies,  which  it  carries  with 
it  till  it  reaches  the  underlying  clay,  where,  on  account  of  the 
compact  nature  of  the  deposit,  the  water  passes  very  slowly  and  so 
allows  a  portion  of  the  elements  which  it  holds  in  solution  to  be  de- 
posited in  the  clay.  Thus  we  have  another  cause  of  the  varieties 
of  clay. 

In  some  cases,  water  percolating  through  clay  does  not  add  im- 
purities, but  probably  tends  to  purify  it.  This  may  be  the  case 
when  coal,  especially  pure  lignite,  overlies  the  clay.  Under  such 
conditions  the  lignite  probably  acts  much  like  charcoal,  as  an  ab- 
sorption filter,  to  remove  matter  in  solution  in  the  water.  The 
water  thus  being  left  quite  free  from  the  lime,  iron,  alkalies,  etc., 
instead  of  contaminating  the  under  clay  might,  whatever  works  its 
way  through,  serve  as  a  wash  to  carry  off  some  of  the  soluble  mat- 
ter of  the  clay.  AVhatever  the  cause,  it  is  a  fact  that  the  purest 
clays  very  commonly  underlie  coal  seams. 

Variations  in  the  character  of  the  rock  from  which  clay  is  de- 
rived, and  variations  to  which  the  clay  is  subject  during  and  after 
deposition,  are  sure  to  produce  clays  of  decidedly  different  char- 
acter. So  it  is  that  we  have  clays  of  all  grades  ranging  from 
those  so  impure  and  mixed  with  sand  and  pebbles  as  to  be  unfit 
for  the  coarsest  uses,  to  those  so  pure  that  from  them  can  be  made 
the  most  beautiful  and  delicate  porcelain  wares. 

Among  the  more  important  uses  to  which  the  coarser  clays  are 
put  is  the  manufacture  of  brick  and  other  architectural  mate- 
rial. Clay  fit  for  this  purpose  is  quite  common,  especially  for 
the  inferior  grades.  The  characteristics  of  clay  suited  to  such 
production,  are  not  necessarily  very  closely  defined.  In  general 
it  may  be  said  that  a  good  material  must  be  free  from  pebbles  and 
from  too  great  a  j^roportion  of  sand,  lime  and  alkalies.  For  the 
common  article  there  is  not  likely  to  be  any  ditficidty  in  finding 
clay  sufficiently  free  from  iron  or  even  alkalies,  though  a  combina- 
tion of  these  elements  in  too  large  a  proportion  often  occurs.  An 
excess  of  lime  may  have  a  tendency  to  give  a  brittle  product  at  a 
low  heat,  or  fusion  at  a  high  heat.  Some  clays,  however,  which 
contain  a  considerable  amount  of  lime  and  alkalies,  if  properly 
handled,  produce  an  excellent  material  where  resistance  and 
abrasive  qualities  are  sought  rather  than  power  to  withstand  in- 


tense  heat.  As  in  all  cases,  the  clay  must  be  suflBciently  plastic 
to  work  well,  and  must  be  tempered,  if  need  be,  so  as  to  prevent 
too  great  shrinkage. 

Cavities  and  fusion  spots  are  often  produced  when  the  material 
used  contains  lime  or  pyrite  nodules  or  fragments  of  organic  mat- 
ter. This  can  be  largely  overcome  by  careful  grinding  and  mix- 
ing. The  color  is  dependent  principally  upon  the  amount  of  iron 
present  and  the  degree  of  heat  to  which  the  clay  is  subjected.  A 
small  proportion  of  iron,  or,  in  other  cases,  a  strong  heat  may 
produce  a  lighter  color  than  would  be  the  case  with  much  iron  or 
a  low  heat.  It  should  be  remembered  that  the  greater  portion  of 
the  produce  of  this  class  is  not  of  tlie  best  grade.  Where  a  su- 
perior quality  can  be  made  there  is  an  enormous  advantage  to  the 
manufacturers  on  account  of  the  greater  demand  and  higher  price 
secured.  The  best  grades  of  brick,  terra  cotta  and  drain  pipes  are 
made  from  inferior  fire  or  potter's  clay. 

Fire  clay  is  the  term  given  to  designate  those  clays  which  pos- 
sess great  fire-resisting  properties.  The  best  of  these  clays  are 
quite  rare,  though  low  grades  are  somewhat  common.  These 
clays  may  vary  much  in  their  original  appearance  from  a  nearly 
pure  white  to  a  slaty  gray  color.  But  they  should  bake  to  a  white 
or  cream  color  without  fusion.  The  essential  qualities  of  fire 
clays  are  plasticity,  great  freedom  from  lime,  and  the  fusing  con- 
stituents, iron,  and  the  alkalies,  soda  and  potash.  Iron  may  exist 
in  clays  in  several  forms;  for  example,  as  peroxide,  protoxide,  sul- 
phate and  sulphide.  But,  in  whatever  form,  unless  in  small  quan- 
tities, it  is  revealed  by  the  ordeal  of  heat  in  the  coloration  and 
the  tendency  to  melt.  The  amount  of  iron  which  a  fire  clay  can 
stand  depends  largely  upon  the  lime,  potash  and  soda  it  has.  A 
clay  containg  only  traces  of  these  fluxing  constituents  may  have 
from  89^  to  5%  of  iron  and  still  possess  considerable  fire-resisting 
power.  If,  however,  a  small  j)roportion  of  lime  and  alkalies  is 
added,  the  clay  is  useless  as  fire  clay.  The  accompanying  two 
analyses  of  the  celebrated  Stourbridge  fire  clay  will  show  the 
variation  in  iron  and  alkalies.     Analyses  by  Prof.  F.  A.  Abel.* 

Sninple.  Silica. 

No.  1 66.47 

No.  2 63.40 

Sample  No.  2,  containing  so  much  less  iron,  is  superior  to  No. 
1,  the  refractory  character  of  which  may  be  doubted.  Lime  and 
magnesia  evidently  exert  a  considerable  influence  upon  the  fusi- 
bility of  clay.  There  has  been  some  difference  of  opinion  among 
chemists  on  this  point.  It  has  been  said  that  the  best  foreign 
fire  clays  seldom  contain  more  than  one  per  cent,  of  lime  and  mag- 
nesia together.  Potash  and  soda  are  doubtless  the  most  powerful 
fluxing    constituents    commonly    found    in    clays.     They    unite 

*  Wagner's  Chemical  Technology,  p.  295. 


Alumina. 

Fe„  O3 

Alkali. 
Waste,  etc. 

26.26 

6.63 

0.64 

31.70 

3.00 

1.90 

readily  with  silica,  forming  the  alkaline  silicates  which  bring 
down  the  fusing  point  to  a  much  lower  temperature.  There  is 
some  difference  of  opinion  in  regard  to  the  amount  of  alkalies  a 
good  fire  clay  will  stand.  Snelus  says  that  about  one  per  cent, 
(of  potash)  is  sufficient  to  render  them  unsuitable  at  high  tem- 
peratures." Bischof  found  that  four  per  cent,  of  potash,  in  a  sili- 
cate of  alumina  without  any  other  bases,  could  be  fused  at  the 
melting  point  of  wrought  iron  *  *  *  Clays  containing  from  two 
to  three  per  cent,  of  potash  are  said  to  stand  well  at  high  temper- 
atures. The  most  carefully  made  analyses  of  the  more  noted  and 
best  fire  clays  of  this  country  and  Europe,  do  not  generally  show 
more  than  two  per  cent,  of  alkalies."  From  the  analyses  of  the 
fire  clays  of  New  Jersey  it  appears  that  "those  which  are  found  to 
have  one  and  a  half  to  two  per  cent,  and  upwards  of  potash  have 
not  proved  to  be  good  fire  clays."t 

The  amount  of  alkalies  admissible  in  a  fire  clay  depends  largely 
uiaon  the  purity,  and  probably  upon  the  physical  condition  of  the 
clay.  Clays  having  much  lime  and  magnesia  or  iron,  can  stand 
but  little  potash  and  soda.  In  a  general  way  it  may  be  said  that 
a  fire  clay  should  not  contain  above  five  per  cent,  of  iron  and  alka- 
lies together.  A  pure  open  body  or  coarse  clay  will  probably 
stand  more  alkalies  than  it  would  if  in  other  condition.  What  has 
been  given  may  be  regarded  as  covering  the  most  essential  char- 
acteristics of  fire  clays.  The  only  way  to  get  a  safe  determina- 
tion of  the  nature  and  value  of  a  given  clay  is  to  consider  the  clay 
as  a  whole,  the  resultant  of  the  action  of  all  its  properties. 

The  following  table  of  analyses  will  give  an  idea  of  the  compo- 
sition of  a  number  of  fire  clays  in  different  localities: 

fNew  Jersey  Geolojrical  Survey,  1878,  "Clays,"  p.  295. 


10 


ANALYSES   OF   FIRE   CLAYS   FROM   VARIOUS   LOCALITIES. 


^ 

c 

0 

c 

0 

■so 

- 

0  o 

CONSTITUENTS. 

g5 

0 

a 
u 
> 

v 

5 

„.5 

II 

o.b 

y.% 

C   . 

7^ 

Z 

■7^? 

b.S 

O  3 

Zii 

1  2 

1  "H 

1  ••' 

\  ii 

■    V 

1  -o 

c5. 

c 

.  c 

0  o 

62 

0^- 

;?; 

2: 

^ 

2; 

Z 

'A 

Z 

^2; 

Z 

74.30 

18.11 

1.C9 

0.11 

67.12 

21.18 

1.85 

0.32 

0.84 

69.25 
17.90 
2.97 

1.30 

48.55 

30.25 

4.06 

1.66 

1.91 

33.40 

31.70 
3.00 

50.00 

31.69 

2.54 

50.80 

31.53 

1.92 

45.60 

38.40 

1.20 

0.22 

0.25 

73.50 

22.70 

1.70 

~1 

i 

trace. 

i 
1 

}•  *2.10- 

0.76 
0.20 

2.02 

^*1.90 

J 

2.22 

0.40 

0.59 

1 

Sodium 

Water    and     volatile 

J 

5.90 

7.11 

7.50 

10.67 

12.65 
.90 

13.80 
1.50 

13.80 

Other  matter 

*Alkalies,  waste,  etc. 

ExPL.\N.\TiON.— No.  1.  New  Jersey  fire  clay,  used  extensively  for  fire  brick,  retorts,  etc. — 
N.J.  Clay  Report,  1878,  p.  248.  ^         ,        ^      ,   .        ^,    , 

.\o.  2.  Fire  clay  from  Dowlais,  South  Wales,  considered  the  best  fire  clay  Dowlais.— N.  J. 
Report  from  Percey's  M«tallury:v. 

Nos.  3  and  4  are,  accordinff  to  Muspratt,  fire  clavs  from  Newcastle-on-Tyne. 

No.  5  is,  apparently,  the  purest  of  several  samples  of  Stourbridjfe,  Eng.,  fire  clay,  analyzed  by 
Professor  Abel.— Wagner's  Chem.  Tech.,  p.  295.  ,      »r      , 

Xos.  6,  7and8.  Analyses  from  N.J.(ieol  Report  (clays),  '78.  No.  8  is  con.sidered  a  No.  1 
fire  clav,  and  is,  perhaps,  a'fair  sample  of  the  New  Jersey  fire  clays. 

No.  9  is  the  analysis  of  a  remarkably  refractory  firebrick  of  the  Cornwall  or  Devonshire 
Kaolin.     Wagner's  Chem.  Tech  ,  p.  321. 

PORCELAIN  AND  EARTHENWARE  CLAY. 

Clays  fit  for  the  manufacture  of  a  high  grade  porcelain  or 
china  are  among  the  rarest  clays  used.  For  such  purposes,  ma- 
terial of  the  utmost  purity  is  required.  The  clay  should  be  suffi- 
ciently plastic  to  be  readily  shaped  and  handled;  when  baked  it 
must  be  pure  white,  or  nearly  so,  and  possess  reasonable 
strength.  To  give  these  results  it  must  be  extremely  free  from 
iron  and  all  foreign  matter  that  would  effect  color.  So  great  free- 
dom from  alkalies  is  not  required  of  porcelain  and  china  clays  as 
for  some  other  purposes,  since  incipient  fusion  is  necessary  to 
produce  the  translucency,  a  characteristic  of  this  kind  of  ware. 

Clays  of  this  kind  are  found  in  a  few  localities  only  and  are  then 
usually  mixed  with  other  carefully  prepared  ingredients.  Material 
is  extensively  prepared  artificially  for  porcelain  and  china.  Clays, 
of  a  slightly  inferior  grade  are  those  used  for  the  production  of 
the  earthenware  which  constitutes  the  most  of  our  common  white 


11 


dish  ware.  The  best  earthenware  clays,  though  not  so  rare  as  the 
china  clays,  are  not  very  common. 

It  is  upon  this  kind  of  clay  that  the  great  pottery  industry  of 
Staffordshire  is  built.  Some  New  Jersey  and  other  clays  are  now 
much  used  in  making  eartheuAvare.  The  seat  of  this  industry  iu 
New  Jersey  is  at  Trenton,  in  Ohio,  at  East  Liverpool. 

Clays  for  good  earthenware  must,  besides  being  plastic,  be  as 
free  from  iron  as  possible,  and  sufficiently  free  from  alkalies  to 
stand  high  heat.  They  should  bake  white  and  give  a  strong  solid 
body.  Most  of  the  requisites  are  those  of  a  first  class  white,  x^las- 
tic  lire  clay.  The  special  differences  are  that  an  earthenware  clay 
should  be  freer  from  iron  than  it  is  necessary  for  a  fire  clay  to  be, 
and  that  a  fire  clay  should  be  freer  from  alkalies  than  it  is  needful 
for  an  earthenware  clay  to  be.  For  the  action  of  the  various  con- 
stituents of  earthenware  clays  refer  to  the  discussion  of  fire  clay 
characteristics. 

"Clay  which  is  pure  white  in  color  and  entirely  free  from  oxide 
of  iron  may  be  intimately  mixed  with  ground  feldspar  or  other 
minerals  which  contain  potash  enough  to  make  them  fusible,  and 
the  mixture  still  be  plastic  so  as  to  be  worked  into  forms  for  ware. 
When  burned,  such  a  composition  retains  its  pure  white  color, 
while  it  undergoes  fusion  sufficient  to  make  a  body  that  will  not 
absorb  water.  And  its  surface  can  be  made  smooth  and  clean  by 
a  suitable  plain  or  ornamental  glaze.  Ware  of  this  kind  is  por- 
celain or  china. 

"  The  large  portion  of  plain  white  and  decorated  wares  now  sold 
as  C.  C.  and  white  granite  wares  are  intermediate  between  the  old 
earthenware  in  which  the  body  was  of  clay  unmixed  and  the  por- 
celain in  which  the  body  is  of  mixed  earths  that  undergo  incipient 
fusion  when  burned  at  a  high  temperature.  The  fine  earthen- 
wares of  both  kinds  mentioned  above  are  being  improved  in  qual- 
ity and  appearance  each  year  and  approaching  nearer  in  real  ex- 
cellence to  porcelain." 

Earthenware  clays  vary  from  those  approaching  nearly  to  china 
clay  to  those  so  impure  (especially  from  iron)  as  to  be  unfit  for 
white  ware  and  called  stoneware  clays.  "  Clay  containing  oxide 
of  iron  in  sufficient  quantity  to  make  it  partially  fusible  in  the 
heat  required  to  burn  it,  when  made  into  forms  and  burned  is 
called  stoneware  clay.  The  heat  is  carried  far  enough  to  fuse  the 
particles  together,  so  that  the  ware  is  solid  and  will  not  allow 
water  to  soak  through  it;  and  the  fusion  has  not  been  carried  so 
far  as  to  alter  the  shape  of  the  articles  burned.  The  oxide  of  iron 
by  the  fusion  has  been  combined  with  the  clay,  and  instead  of  its 
characteristic  red  has  given  to  the  ware  a  bluish  or  grayish  color. 
Stoneware  may  be  glazed  like  earthenware,  or  by  ijutting  salt  in 
the  kiln  when  its  vapor  conies  in  contact  with  the  heated  ware 
and  makes  with  it  a  sufficient  glaze."  Clay  of  this  kind  is  used 
largely  for  finer  grades  of  jars,  jugs,  etc. 


12 


A  considerable  variety  of  products  may  be  gotten  by  a  judicious 
mixture  of  fine  and  inferior  clays.  The  following  table  of  anal- 
yses will  show  the  composition  of  a  number  of  china  and  earthen- 
ware clays  from  different  localities  : 


CONSTITUENTS. 

V 
u 

S 

>-> 
u 

V. 

li    . 
— >>^ 
>  J5 

0 

=1 

c 
c 
O    . 

>;^ 

a", 
11 

Dorsetshire    clav, 
used     in      Staf- 
fordshire     pot- 
teries. 

11 

SOX- 

c 

1 

]3 
u 
I., 
o 

Oh 

No.   1 

No.  2 

No.  3 

No.  4 

No.  5 

No.  6 

No.  7 

45.45 

38  75 

1.15 

43.40 

37.56 

1.04 

69.03 

23.89 

0.45 

0.29 

0.05 

66.20 

24.11 

0.79 

■'0.'96 

46.38 

38.(4 

1.04 

1  20^ 

trace  ) 

13.44 i 

35.65 

32.50 

1.65 

trace 

30  05 

(  loss 
?0.15 

66.60 

28.00 

0.70 

0.30 

0.11 
0.17 

■is.cs' 

1.32 

"'o.'ss' 

0.37 
15.40 

1.40 

0.60 

3.40 

Water  and  volatile  matttr 

7.46 

7.20 
0.20 

Nos.  1  and  2.  —From  New  Jersey  Clay  Report  of  1878. 

Xo.  3.— From  analysis  made  of  clay  from  a  Trenton  pottery,  mixed  and  proportioned  ready 
for  use. 

No.  4.— From  Williams'  Applied  Geology. 

No.  5.— Muspratt  gives  this  analysis  by  Mr.  Higginbolham,  of  clay  ssed  in  Staffordshire 
potteries. 

No.  6.— From  Muspratt;  Cornish  stone  clay  so  extensively  used  in  fine  white  ware  and  china 
clay,  in  the  impure  state. 

No.  7. — From  Muspratt,  Laurent,  analyst,  (supposed  to  be  from  the  ware,  not  the  clay.) 

From  what  has  been  said  it  will  appear  that  the  better  grades 
of  earthenware  clay  are  occasionally  found  of  sufficient  purity  to 
be  used  in  the  manufacture  of  china,  porcelain  and  semi-porcelain 
wares,  while  the  inferior  qualities  run  gradually  into  clays  used 
for  stoneware,  etc.  Those  clays  not  sufficiently  pure  for  high 
grade  stoneware  may  be  used  in  the  manufacture  of  Kockingham 
and  other  ware.  Stoneware  clay  may  also  be  used  for  a  very  fine 
quality  of  drain  pipe;  but  for  much  of  the  common  drain  pipe 
propably  no  better  than  common  brick  clay  is  used.  Earthen- 
ware clay  may  also  be  used  as  a  fire  clay  in  many  cases  and  fire 
clays  may  in  turn  be  used  for  earthenware.  In  fact  the  very  best 
fire  clays  of  some  districts  are  practically  the  same  as  those  used 
fox  fine  earthenware. 

In  considering  the  characteristics,  etc.,  of  clays,  only  three 
divisions  have  been  made,  viz:  (1.)  Coarse  clays  used  for  bricks 
and  terra  cotta,  etc. ;  (2. )  Kefractory  clays  used  for  fire-brick,  fur- 
nace linings  and  various  other  purposes  where  exposure  to  great 
heat  is  necessary;  (3.)  Earthware  clays  used  for  the  manufacture 
of  white  dishware. 

Without  going  into  a  further  study  of  the  varieties  of  clays,  we 
may  take  the  three  groups  already  considered  as  central  types,  to 


13 


■which  may  be  referred,  as  modified  forms,  most  other  clays  suited 
to  uses  we  have  not  considered. 

LOCAL   DESCRIPTIONS. 

Brick  Clay. — Clays  suited  to  the  manufacture  of  brick  are,  for- 
tunately, very  widely  distributed.  The  quality,  however,  varies 
much,  and  gives  rise  to  products  varying  greatly  in  value. 

North  Dakota  is  remarkably  well  supplied  with  good  brick  clays. 
They  are  so  well  known  that  but  little  need  here  be  said  in  regard 
to  them.  Fair  brick  clays  may,  I  think  be  found  in  most  parts  of 
the  State.  Over  a  considerable  district  in  the  eastern  part,  these 
clays  appear  in  two  distinct  beds;  i.  e.,  the  upper,  usually  yellow 
clay,  immediately  under  the  soil,  and  the  deeper  blue  clay.  In 
most  if  not  all  cases  in  this  district,  brick  is  made  from  the  yellow 
clay.  Still  it  is  quite  probable  that  a  judicious  and  thorough  mix- 
ture of  the  blue  and  yellow  clays  would  jjroduce  a  better  article. 

In  the  north  central  portion  of  the  state,  there  are  near  the  sur- 
face, shale  deposits  of  considerable  thickness  which  would  doubt- 
less in  many  cases  make  excellent  brick  and  drain  pipe. 

In  the  western  portion  of  the  state  there  is  a  variety  of  clays. 
In  many  localities  the  poorer  coal  clays  may  produce  fine  brick, 
drain  and  sewer  pipe  and  terra  cotta.  The  coal  clays  of  medium 
qualities  in  some  places  will  produce  exceedingly  fine  facing  brick 
and  fancy  architectural  and  decorative  material. 

It  is  probable  that  the  shales  about  Park  River,  Milion,  Lang- 
don,  etc.,  along  the  Great  Northern  railroad  to  the  north,  will  pro- 
duce good  brick  and  drain  pipe  if  properly  utilized.  They  would 
be  likely  to  produce  a  firm  siliceous  red  brick. 

Near  Minoi,  Ward  Countij  and  Wilh'sfon  on  the  main  line  of 
the  Great  Northern  railroad,  there  are  clays  that  will  make  a  fine 
dense  brick  and  drain  pipe  in  color  from  light  cream  to  red. 

Near  Bismarck  there  are  two  or  three  layers  of  clay  fit  for  ex- 
cellent red  brick.  On  the  bank  of  the  Missouri  river,  north  of 
the  Northern  Pacific  railroad  bridge,  near  Bismarck,  two  layers 
appear  well  suited  to  this  use  as  well  as  to  the  production  of  good 
drain  and  sewer  .pipes.  One  of  these  clays  is  a  rather  sandy  gray 
clay;  under  this  is  a  dark  carbonaceous  clay  somewhat  plastic  and 
apparently  adapted  for  making  strong,  dense  drain  pipe,  roofing 
tile,  brick,  etc. 

About  Dickinson  the  great  variety  of  fine  clays  afford  abundant 
material  for  the  finest  kind  of  brick,  terra  cotta,  pipe  material  of 
differen  t  kinds,  etc.  The  best  of  these  clays  run  into  fine  fire 
clay  and  earthenware  clay,  and  seem  too  valuable  to  be  used  for 
common  brick.  They  will  be  further  considered  under  the  head 
of  fire  and  earthenware  clay. 

In  the  Bed  Biver  Valley  the  yellow  clay  immediately  under 
the  soil  affords  material  for  a  first  class  cream  brick.  It  is  the 
clay  used  extensively  at  Grand  Forks,  and  if  thoroughly  mixed 


14 


and  formed  by  a  high  pressure   machine,  will  undoubtedly  pro- 
duce a  superior  brick. 

The  following  are  analyses  of  several  North  Dakota  clays  which 
may  be  used  for  brick,  etc.f 


CONSTITUENTS. 


Silicon  (Si  O,  )  

Aluminum  (Al,  O    ) 

Iron  Oxide  (Fe,  O3  ) 

Calcium  (Ca  O) 

Magnesium  (Mg  O) 

Sodium  (Na,  O) 

Potassium  (K,  O) 

Water  and  Volatile  Matter  *. 
Other  Matter 


Grand  Forks. 


51.27 
9.33 
3.52 

11.15 
2.31 
2.08? 
0.50? 


Bismarck. 


58.73 
14.98 
5.63 
2.10 
0  74 
0.988 
0.16 
16.672 


W'illiston. 


57.80 
9.47 


*  By  Subtraction.     All  very  moist. 

Remarks. — No.  1,  clay  used  at  Alsip's  Brick  Works.  No.  2,  not  used;  found 
on  bank  of  Missouri  River  near  Bismarck.  No.  3,  not  used;  associated  with 
coal  near  Williston.  In  the  laboratory  furnace,  No.  1  baked  cream;  No.  2, 
red,  very  firm;  No.  3,  cream. 

Fine  Architectural  and  Semi-Fire  Material,  Tile,  Drain 
AND  Sewer  Pipe,  Etc. — Most  of  the  coarser  grade  of  tile,  drain  and 
sewer  pipe  may  be  made  from  common  brick  clay,  but  the  best  of 
such  material  is  a  little  more  exacting  in  its  clay  used,  although 
it  is  very  often  classed  with  brick  clay.  Under  brick  clay,  some 
places  were  mentioned  where  doubtless  fair  tiling  and  pipe  clay 
may  be  found. 

Clays  fit  for  high  grade  articles  of  this  kind  should  possess 
sufficient  plasticity  and  tenacity  to  be  readily  moulded  into  varied 
shapes,  and  strength  to  resist  too  easy  crushing.  They  must  have 
enough  quartz  material  to  prevent  cracking  and  shrinking,  and  for 
many  purposes  should  be  quite  refractory  since  they  are  baked  at 
strong  heat  and  may  in  after  use  be  exposed  to  high  temperatures. 

A  considerable  difference  in  the  product  may  be  made  by  the 
use  of  a  good  plastic  clay  and  varying  proportions  of  sand. 

At  Minot,  Ward  connhi,  on  the  main  line  of  the  Great  Northern 
Railway,  one  or  two  very  good  clays  are  found  associated  with  the 
coal  of  that  locality.  A  few  miles  northwest  of  Minot  coal  is 
mined  from  the  bluffs  that  rise  from  the  old  valley  of  the  Souris 
river.  At  Colton's  mine  the  coal  is  found  in  a  nearly  horizontal 
layer,  probably  8  to  12  feet  thick  and  about  12  feet  below  the  top 
of  the  bluff.  Most  of  the  cov^ering  material  above  the  coal  ap- 
pears to  be  clay  and  sand.  Just  above  the  coal  there  is  a  layer  of 
fine  clay  of   a  slaty  gray  color   and  a  smooth   greasy  feel.     The 


fThe  analvses  of  North  Dakota  ciavs  used  in  this  report  have  been  made  in  the  chemical 
laboratorv  of  the  State  University.  In  making'  the  an.alyses  the  author  has  been  assisted  by  Mr. 
Myron  W.  Smith,  B.  S.,  who  has  been  a  post  graduate  student  in  this  University.  The  alkalies, 
in  all  cases,  were  determined  by  the  writer. 


15 


layer  appears  to  be  several  feet  thick.  This  clay  would  probably 
make  an  excellent  architectural  material  for  the  finer  ornamental 
purposes.  It  seems  to  possess  some  refractory  power,  and  with  a 
proper  admixture  of  sand  would  be  likely  to  make  a  fine  drain  and 
sewer  pipe  and  a  fair  semi-fire  brick.  In  the  laboratory  it  bakes 
to  a  light  reddish  cream  and  becomes  very  firm.  Its  composition 
is  shown  by  the  following  analysis  : 

Silicon  (  Si  O2  ) 56.86 

Aluminum  (  AI2  O3  ) 25.03 

Iron  Oxide  (  Fe2  O3  ) 6.11 

CHlcium  (Ca  O) 0.71 

Magnesium  (Mg  O) 0.76 

Potassium  (K2  O) 0.50 

Sodium  (Na2  O) 0.016 

Water  and   volatile   matter 
Other  matter    


[By  subtraction 10.014 


It  will  be  seen  that  there  is  a  rather  large  proportion  of  iron 
for  a  high  grade  fire  material.  But  its  composition  is  apparently 
all  right  for  the  purposes  mentioned,  i.  e.,  drain  and  sewer  pipe, 
semi-fire,  ornamental  material,  etc. 

In  Mercer  county  at  the  Plenty  coal  mine  on  the  Missouri  river, 
a  clay  is  found  associated  w^ith  the  coal  which  is  very  similar  to 
the  Minot  clay  just  described.  It  has  about  the  same  texture, 
color  and  feel  and  after  being  baked  looks  much  the  same.  It 
could  therefore  be  used  for  the  same  purposes  as  the  Minot  clay. 
The  analysis  of  this  clay  is  as  follows: 

Silicon  (Si  O2  ) 60.79 

Aluminum  (  AI2  0:0 16.23 

Iron  Oxide  (  Fe2  O3  ) 4.49 

Calcium  Oxide  (Ca   O) 0.65 

Magnesium  Oxide  (Mg  O) 1 .02 

Potassium  Oxide  (K2  O) 0  19 

Sodium  Oxide  (Na2  O) 0.28 

Water  and  volatile  matter . . . .  [  ^R  ^~ 

Other  matter  by  subtraction  S '  "^ 

Northeast  of  Langdon,  in  the  Pembina  Mountains,  in  the  vicin- 
ity of  Olga  village,  a  remarkably  fine  white  clay  is  found  in  thin 
layers  outcropping  along  the  hill.  The  layers  which  have  been 
seen  by  the  writer  are  probably  not  of  sufficient  thickness  to  be  of 
use,  but  from  the  reports  of  others  there  seem  to  be  thick  deposits. 
An  illustration  on  page  31,  shows  how  the  thinner  layers  occur. 
This  clay  is  very  white,  of  a  soapy  feel,  and  very  fine  in  texture. 
It  is  also  acid  to  the  taste  and  to  litmus,  and  bakes  to  a  hard, 
strong  body  of  a  pinkish  color.  The  acid  element  is  sulphuric 
and  may  partially  exist  as  a  natural  alum.  This  clay  would 
doubtless  by  washing  be  well  fitted  for  the  manufacture  of  semi- 
fire  brick,  fine  drain  pipe,  ornamental  material  of  various  kinds 


16 


and  for  finer  stoneware.     Au  analysis  of  this  clay  gives  the  follow- 
ing results: 

Silicon  (  Si  0-2  ) 50.45 

Aluminum  (  Al2  O3  ) 17-57 

Iron  Oxide  (  Fe2  O3  ) 2.80 

Calcium  Oxide  (Ca   O) 0.25 

Magnesium  Oxide  (Mg  O) 1 .  79 

Potassium  Oxide  (K2  O) 0-07 

Sodium  Oxide  (Na2  O) 0.86 

Water  and  volatile  matter 22.55 

Other  matter  and  errata 3.66 

At  Bismarck,  along  the  bank  of  the  river  near  the  Northern 
Pacific  railroad  bridge,  there  are  two  layers  of  clay  both  of  which 
may  be  used  for  the  purposes  described  in  this  section.  These 
two  clays  occur  about  50  feet  above  the  river.  The  upper  layer  is 
several  feet  thick,  is  of  a  dark  grayish  color  and  mixed  with  a 
little  finely  pulverized  sand.  Just  under  this  is  a  finer,  more 
plastic,  chocolate-colored  clay  of  uniform  texture.  The  color  is  due 
in  part  to  the  presence  of  carbonaceous  matter.  On  burning,  it 
becomes  a  light  red.  When  baked,  it  posseses  a  hard,  compact, 
ringing  body.  The  thickness  of  the  layer  is  not  known,  but  of 
the  two  layers  there  is  probably  a  deposit  of  not  less  than  six  or 
eight  feet.  There  is  but  little  doubt  that  this  clay  would  be  value 
able  for  several  uses.  It  could  be  mixed  with  the  clay  above  in 
which  is  much  like  it  and  would  then  make  an  excellent  drain  and 
sewer  pipe  and  a  good  ornamental  building  material.  An  analysis 
of  this  clay  shows: 

Silicon  (Si  2  O) 58. 73 

Aluminum  (AI2  O3  ) 14.98 

Iron  Oxide  (Fe2  O3  ) 5.63 

Calcium  Oxide  (Ca  O) 2.10 

Magnesium  Oxide  (Mg  O) 074 

Potassium  Oxide  (K2  O) 0.16 

Sodium  Oxide  (Na2  O) 0.988 

Water  and  volatile  matter I  -.q  g-^ 

Other  matter,  by  subtraction ) 

It  is  quite  possible  that  the  shales  seen  near  Park  River  and 
Langdon  along  the  Great  Northern  Railway  may  prove  suitable 
for  drain  pipe. 

About  Dickinson  there  is  a  great  variety  of  clays,  some  of  which 
being  too  poor  iov  earthenware  and  fine  refractory  material,  will 
make  good  semi-fire-brick  and  other  inferior  refractory  articles, 
besides  tiles,  pipes,  and  the  fiuest  ornamental  building  material. 
By  mixing  the  clays  found  in  this  vicinity,  material  can  be  had 
for  a  large  number  of  uses.  A  mottled  clay,  said  to  occur  in  large 
quantities,  seems  remarkably  well  suited  to  the  manufacture  of 
terra  cotta  and  ornamental  material.  This  clay  appears  very 
much  like  some  of  the  mottled  clay  from  Martha's  Yineyard.  It 
has  a  fine  white  body  dotted  with  patches  of  red.     It  is  all  very 


17 


free  from  grit  and  when  ground  makes  a  uniform  body  of  a  light 
red  color.  It  is  very  plastic,  but  stands  heat  well  without  cracking 
or  warping.     The  following  is  an  analysis  of  this  clay : 

Silicon  (Si  O2  ) 56.03 

Aluminum  (AI2  O3  ) 24.23 

Iron  Oxide  (Fe2  O3  )  9-46 

Calcium  Oxide  (Ca  O) 

Magnesium  Oxide  (Mg  O) 0.31 

Potassium  Oxide  (K2  O) 0.088 

Sodium  Oxide  (Na2   O) 0.72 

Water  and  volatile  matter 9.39 


This  clay  will  be  seen  to  be  remarkably  free  from  all  fusing 
constituents  excepting  iron.  By  properly  mixing  with  the  fine 
white  clay  found  in  the  same  locality  (described  under  fire  and 
earthenware  clay)  a  fairly  refractory  material  would  be  gotten,  fit 
for  some  grades  of  fire  brick,  saggars  and  many  other  purposes. 

A  few  miles  east  of  Dickinson,  at  the  Lehigh  mine  on  the 
Northern  Pacific  Railway,  the  clay  which  underlies  the  coal  may, 
without  doubt,  be  used  for  some  of  the  purposes  mentioned  in  this 
section.  At  this  place  lignite  coal  is  quite  extensively  mined. 
The  nearly  horizontal  layer  of  coal  outcrops  from  the  side  of  a 
bluflf,  about  100  feet  or  250  feet  below  the  top,  and  is  from  8  feet 
to  15  feet  or  more  in  thickness.  It  is  mined  by  a  tunnel  from  the 
side.  The  coal  is  capped  by  a  layer  of  pure  gray  clay  5  to  10  feet 
thick,  which  may  be  used  for  common  brick,  and  will  probably  do 
well  for  terra  cotta,  drain  pipe,  etc.,  where  not  subject  to  strong 
heat.     The  analysis  of  this  clay  gives: 

Silicon  (Si  O2  ) 55.77 

Aluminum  (AI2  O3  ) 12.15 

Iron  Oxide  ( Fe2  O3  ) 4  27 

Calcium  Oxide  (Ca  O) 5.92 

Magnesium  Oxide  (Mg  O) 1.90 

Potassium  Oxide  (K2  O) 0.256 

Sodium  Oxide  (Na2  O) 0.992 

Water  and  volatile  matter,  etc.,  by  subtraction 18.742 

This  clay  bakes  to  a  buff  color,  stands  low  heat  well,  but  shows 
a  tendency  to  fuse  at  high  temperature. 

The  clay  under  the  coal  is  of  better  quality  than  that  above.  It 
is  dark  colored  and  of  a  soapy  feel.  The  dark  color  appears  to  be 
due  to  the  large  amount  of  carbonaceous  matter.  When  baked  it 
takes  on  a  light  gray  color. 

The  following  illustration  will  give  an  idea  of  the  formation. 
The  outcrop  which  appears  in  this  cut  is  some  distance  from  the 
mine.  It  sliows  only  a  small  portion  of  the  layer  of  coal  and  none 
of  the  under  clay. 

Coal— 2 


18 


The  following  is  an  analysis  of  the  under  clay  after  burning  to 
remove  carbon: 

Silicon  (  Si  O2  ) 71.25 

Aluminum  (AI2  O3  ) 21.94 

Iron  Oxide  (Fe2  03  ) 3.67 

Calcium  Oxide  (Ca  O) 0.74 

Magnesium  Oxide  ( Mg  O) 0.83 

Potassium  Oxide  (K2  O) 

Sodium  Oxide  (Na2  O) 

Water  and  volatile  matter,  by  subtraction 

About  Dickinson,  higher  grade  clays  abound  which  are  too  val- 
uable to  be  used  for  the  purposes  named  in  this  division.  These 
will  be  considered  under  fire  and  earthenware  clays. 

For  comparison,  we  insert  the  following  analyses  of  clays  of  this 
character  found  in  other  localities,  and  used  for  the  purposes  we 
have  just  considered: 


CC^STITUENTS. 

d 

12; 

0 

5 

[6 

U 

dsJ 

-0 

0 
BC 

1     . 
"^ 

do 
Z 

c 

"c 

V 

c 

lo 
dsi 

r;  i) 

•z 

E 
« 

In 

dg 

Silicon .... 

69.59 

20.04 

3.37 

3.16 

3.18 

57.83 
20.55 
7.75 
1.68 
0.97 
3.87 
.56 

6.52 
0.90 

64.06 
20.60 
7.16 
0.12 
0.04 
0.91 
0.44 

5.85 
0.71 

64.14 

13.34 

7.57 

1.90 

54.38 

26.55 

8.38 

58  07 

Aluminum 

27.38 

Iron 

3  30 

Calcium 

0  50 

Magnesium 

Potassium 

1.54 

-, 

Sodium 

I  10.30 

Water,  organic  matter  and 

loss 

7.28 
3.14 

Other  constituents 

■' 

Nos.  1,  2,  3  and  4  are  terra  cotta  and  tile  clay  analyses  taken 
from  Spon's  Encyclopedia  of  Industrial  Arts,  and  are  said  to 
stand  fire  well  and  to  be  much  used. 

No.  5,  Staffordshire  saggar  clay,  ''Burns light  buff,  a  firebrick," 
from  Dobson's  Brick  and  Tile,  p.  115. 

No.  6,  "A  yellow  midland  counties  clay,  used  for  brick  and  Rock- 
ingham pottery,"  Dobson's  Brick  and  Tile,  p.  264. 

The  following  are  analyses  of  North  Dakota  clays  thought  fit 
for  tile,  terra  cotta,  drain  and  sewer  pipe,  etc.: 


< 

o 
u 

o 
E 


19 


CONSTITUENTS. 


Silicon  (Si  O2  ) 

Aluminum  (AI2  O3  ) 

Iron  (Fe2  O3  ) 

Calcium  (Ca  O) •... 

Magnesium  (Mg  O) 

Potassium  (K2  O) 

Sodium  (Na2  O) 

Water  and  volatile  matter,  etc. 
Other  matter  and  errata 


1^  ^ 

o 
do 


86 

03 

11 

71 

76 

50 

016 

014 


GO.  79 
16.23 
4.49 
0.65 
1.02 
0.19 
0.28 
16.35 


0  = 


dCuC 


50.45 
17.57 
2.80 
0.25 
1.79 
0.07 
0.86 
22.55 
3.66 


I  J- 3 


d  ES 


58.73 
14.98 
5.63 
2.10 
0.74 
16.672 
0.988 
0.16 


o  . 
^^ 

dn 
•z, 


31 
088 
72 
39 


JO 


®  cs.S 

duS 


55.77 
12.15 
4.27 
5.92 
1.90 
0.25G 
0.992 
18.742 


71.25 

21.94 

3.67 

0.74 

0.83 


By  a  comparison  of  an  analysis  of  these  clays  with  the  preced- 
ing analyses  given  of  clays  from  England  and  other  localities, 
used  for  the  purposes  under  consideration,  it  will  be  seen  that 
with  one  or  two  exceptions  the  North  Dakota  clays  are  of  con- 
siderably better  quality.  In  nearly,  if  not  all  cases,  the  clays  are 
easily  mined.  In  most  cases  they  are  found  immediately  asso- 
ciated with  coal  or  where  it  can  be  had  at  small  cost.  This  is  a 
great  advantage  to  North  Dakota  clays.  The  fuel  question  is  one 
of  paramount  importance,  since  it  is  one  of  the  largest  sources  of 
expense  in  the  manufacture  of  clay  products.  The  abundance  of 
fuel,  which  can  be  gotten  for  a  mere  trifle  where  most  of  these  clays 
are  found  in  North  Dakota,  will  aid  wonderfully  in  making  the 
manufacture  of  clay  articles  an  extensive  and  profitable  industry. 

Fire  Clay,  Etc. — We  now  come  to  the  consideration  of  one  of 
the  rarest  and  most  valuable  of  clays.  Fire  clay  is  sought  for  a 
number  of  important  uses  for  which  ordinary  clay  is  far  too  poor 
and  for  which  no  other  kind  can  be  satisfactorily  used.  The  fol- 
lowing are  some  uses  to  which  a  good  fire  clay  is  put,  viz.,  for  fire, 
brick,  retorts  for  gas  works,  glass  works  and  metal  works,  for  cru- 
cibles, for  special  use  in  fire-proof  buildings,  and  in  furnaces, 
ovens,  flues,  fire-proof  safes,  etc.,  etc. 

The  essential  characteristics  of  fire  clay  have  already  been  con- 
sidered. (See  pages  8-11. )  In  the  last  section  we  mentioned 
or  two  clays  which  may  be  regarded  as  fire  clays,  but  they  are  of 
inferior  quality.  The  finer  fire  clays  are  not  essentially  difl'erent 
from  fine  earthenware  clays  and  are  often  extensively  used  for 
pottery.  There  is  only  one  locality  in  North  Dakota  known  to 
the  writer  where  the  finest  grade  of  fire  clay  is  found. 

About  Dickinson,  Stai-k  countji,  there  are  several  clays  which 
may  be  considered  first  quality  fire  clays.  The  origin  of  these 
clays  can  only  be  guessed.     It  has  already  been  stated  that  they 


20 


are  found  in  the  Laramie  formation.  The  finest  clays  in  this  lo- 
cality occur  in  elevations  100  feet  or  more  above  the  surrounding 
valley.  These  clay  knolls  have  escaped  much  of  the  erosion  to 
which  the  surrounding  country  has  been  subjected.  If  these  de- 
posits ever  extensively  covered  the  plain  far  east  of  Dickinson, 
they  have  probably  been  mostly  or  entirely  removed  by  the  longer 
action  of  the  receding  water,  glacial  or  post-glacial, as  it  narrowed 
to  the  present  basin  of  the  Missouri  river.  The  ultimate  source  of 
these  deposits  is  a  matter  for  conjecture.  It  is  not  impossible 
that  they  were  once  feldspatic  rocks  occurring  to  the  west  and 
northwest  along  the  flank  of  the  Rocky  Mountains. 

The  clays  of  this  character  which  the  writer  has  examined, 
about  Dickinson,  outcrop  from  near  the  top  of  high  bluffs.  (!See 
cut  on  page  27. )  In  some  cases  the  surface  soil  and  clay  seems  to 
have  been  entirely  washed  away  and  the  white  fire  and  earthen- 
ware clay  is  left  capping  the  bluff.  This  is  the  case  with  a  de- 
posit of  very  fine  clay  which  occurs  about  one  mile  south  of  Dick- 
inson. At  this  point  the  bluff  is  about  100  feet  high.  The  base 
appears  to  be  principally  of  sand  and  clay.  Above  this  is  a  very 
thick  layer,  probably  from  ten  to  fifteen  feet  of  fine  white  fire 
clay;  above  this  is  a  layer  perhaps  four  feet  thick,  of  still  purer 
white  clay,  which  caps  the  hill  where  not  washed  away.  This  up- 
per clay  is  intimately  mixed  with  a  small  amount  of  sand,  which 
gives  it  a  rough  feel.  As  taken  from  the  layer,  the  lumps  are  soft 
enough  to  be  crushed  in  the  hand.  When  baked  it  produces  a 
hard  body  which  shows  a  tendency  to  fuse.  The  color  becomes  a 
pure  white,  purer  than  before  baking,  which  indicates  that  a  small 
amount  of  carbonaceous  matter  was  present  in  the  unbaked  ma- 
terial.    An  analysis  of  this  clay  shows  the  following: 

Silicon  (Si  O2  ) 72.66 

Aluminum   ( AI2  O3  ) 17.33 

Iron  rFe2  O3  ) 1.05 

Calcium  (Ca  O) 0.13 

Magnesium  (Mg  O) 

Potassium  (K2  O) 0.36 

Sodium   (Na2  O) : 0.38 

Water  and  volatile  matter  I  q  oc 

Other  matter                        ^  * " ^-^^ 

From  the  analysis  it  will  be  seen  that  this  is  a  very  pure  clay. 
The  silicon  appears  rather  high  in  proportion  to  the  aluminum,  but 
this  is  due  to  the  presence  of  a  small  amount  of  sand  which,  if 
necessary,  could  be  removed  with  little  trouble.  For  most  pur- 
poses the  silicon  does  not  appear  too  high.  The  iron,  it  will  be 
noticed,  is  very  low,  while  there  is  scarcely  more  than  a  trace  of 
calcium,  and  the  alkalies  are  also  low.  In  all  respects  this  clay 
seems  to  be  an  exceedingly  fine  fire  clay. 

The  clay,  as  has  been  stated,  found  immediately  under  this,  is  a 
layer  about  ten  feet  thick.     It  is  very  fine  and  free  from  grit,  and 


21 


can  be  dug  with  a  spade  and  pulverized  in  the  hand.  Its  color 
when  dug  is  grayish  white,  probably  due  to  a  slight  amount  of 
carbonaceous  matter,  but  after  baking  it  becomes  a  pure  white. 
It  has  a  very  firm  homogeneous  body,  and  when  baked  becomes 
very  hard  with  a  clear,  sharp  ring.  This  clay  has  been  subjected 
to  intense  heat  in  the  laboratory  furnace  and  stands  perfectly 
without  cracking  or  warping.  The  analysis  of  a  sample  taken 
from  a  surface  exposure  gives — 

Silicon  (Si  O2  ) 64.84 

Aluminum  (AI2  O3  ) 24.31 

Iron  (Fe2  03  ) 1.60 

Calcium  (Ca  O) 0.11 

Magnesium  (Mg  O) 0.24 

Potassium  (K2  O) trace 

Sodium  (Na2  O) 0.32 

Water  and  volatile  matter )      q  ^o 

Other  matter S 

This  analysis  shows  a  very  pure  clay  and  one  well  proportioned 
for  immediate  use.  The  fluxing  constituents  are  so  small  in 
amount  as  hardly  to  need  notice.  The  iron  is  also  small  for  an 
univashed,  surface  specimen.  The  surroundings  are  all  that  could 
be  desired.  At  the  foot  of  the  blufp  where  the  clay  is  found  there 
is  a  small  stream  which  would  furnish  water  to  a  factory.  The 
deposit  is  probably  not  more  than  one  and  a  half  miles  from  the 
main  line  of  the  Northern  Pacific  railway,  so  a  spur  track  could 
easily  be  ruu  to  it.  Coal  is  mined  within  a  few  miles  and  can  be 
had  at  very  low  rates.  There  is  no  doubt  but  what  this  clay,  as 
well  as  the  one  mentioned  before  it,  is  unusually  well  suited  for 
the  highest  grade  of  fire  material,  and  there  seems  to  be  an  abund- 
ance of  it. 

There  are  doubtless  several  other  deposits  of  excellent  fire  clay 
in  this  vicinity  although  the  writer  has  not  visited  others.  How- 
ever, samples  of  a  number  of  excellent  clays  have  been  secured 
and  analyzed.  In  most  cases  these  samples  are  much  the  same  in 
general  appearance  as  the  ones  just  described.  One  or  two  sam- 
ples show  a  very  slight  cream  tint  after  baking.  They  generally 
bake  white  and  very  hard.  An  analysis  of  a  sample  furnished  by 
Mr.  E.  F.  Messersmith  gave  the  following  results: 

Silicon  (Si  O2  ) 64.22 

Aluminum  (AI2  O3  ) 17.22  (?) 

Iron  (Fe2  O3  ) 2.09 

Calcium  (Ca  O) trace 

Magnesium  (MgO) 0.37 

Potassium  (K2  O) 0  21 

Sodium  (Na2  O) 0.34 

Water  and  volatile  matter 10.29 

In  the  Pembina  Mounfains  there  is  found  a  fine  white  clay 
which  may  be  regarded  as  a  medium  fire  clay.  The  extent  of  this 
clay  is  not  known,  but  from  reports  which  have  come  in,  it  seems 
to  be  in  abundance.     As  dug,  it  is  quite  white.     When  baked  at  a 


22 


high  temperature  in  the  laboratory  furnace^  it  assumes  a  slightly- 
pinkish  tint.  This  clay  would  probably  require  careful  washing. 
It  appears  to  be  slightly  impregnated  with  alum.  An  analysis  of 
this  clay  is  as  follows* 

Silicon  (Si  O2  ) 50.45 

Aluminum  (AI2  O3  ) 17.57 

Iron  (Fe2  O3  ) 2.80 

Calcium  (Ca  O) 0.25 

Magnesium  (Mg  O 1.79 

Potassium  (K2  O) 0.07 

Sodium  (Na2  O) 0.86 

Water  and  volatile  matter 22.55 

Other  matter  and  errata 3.66 

This  sample  was  found  near  Olga.  An  idea  of  its  occurrence' 
may  be  gotten  by  referring  to  cut  on  page  31.  Fire  clays  of  this 
quality  may  be  found  in  other  localities,  but  they  are  not  known 
to  the  writer.  For  the  purpose  of  comparison,  the  analyses  are 
given  of  a  number  of  fire  clays  found  in  different  parts  of  the 
world,  and  extensively  used  for  various  refractory  puj-poses. 

TABLE    "a." 


>> 

D 

0 

•0 

^ 

^ 

•ot; 

C 

c 

c 

'  Y. 

0 

s 
0 

c 
0 

a 

0 

c 

Q 

u 

Analyses  of    Fire 

_u 

_u 

bb 

P 

0)   X 

«  1) 

it 

•3.H 

Clays    from    Va- 

—> 

rt 

u 

^ 

^j: 

u 

?^ 

l^ 

rious  Localities. 

S 

J 

^ 

3 

0   u- 

1 

Q 
1 

z 

1 

Z 
1 

1 

fa 
1 

0 
1 

z. 

1 

U£. 

(TJ 

00 

ui 

«D 

06 

».!: 

0 

0 

0 

0 

0 

6 

0 

0 

d-S 

z 

Z 

z 

z 

Z 

Z 

Z 

z 

z 

74.30 

IS.ll 
1.09 
0.11 

67.12 
21.18 

1.85 
0.32 
0.84 

69.25 
17.90 
2.97 

1.30 

48.55 

30.25 

4.06 

1.66 

1.91 

63.40 

31.70 

3.00 

50.00 

31.69 

2.54 

50.80 

31.53 

1.92 

45.60 

38.40 

1.20 

0.22 

0.25 

73.50 

22.70 

1  70 

1 

Trace. 

|-t2.10 

0  78 

2.02 

2.22 

0.40 

0..59 

0.20 
5.90 

h*1.90 

i 
1 

J 

Water  antl  Volatile  ? 
Matter  . .      ) 

7.11 

7.50 

10.67 

12.65 

13.80 

13.80 

0.90 

1.50 

*  Alkalies,  waste,  etc. 

t  Alkalies  and  waste. 

No.  1.  New  Jersey  fire  clay,  used  extensively  for  fire  brick,  retorts,  etc.  N.  J.  Clay  Report,, 
p.  248. 

No.  2.  Fire  elay  from  Dowlais,  South  Wales,  considered  the  best  fireclay  in  Dowlais.  N.  J. 
Report  from  Percy's  Metallurg-y. 

Nos.  3  and  4  are,  according:  to  Muspratt,  fire  clays  from  Newcastle-onTyne. 

No.  5  is,  apparently,  the  purest  of  nine  samples  of  Stourbridge,  Kng.,  fireclay,  analyzed  by 
Prof.  Abel.     Wagner's  Chem.  Tech.,  p.  295. 

Nos.  6,  7,  and  8.  Analysis  from  N.J.  Geol.  Report  (Clays),  '78.  No.  8  is  considered  a  number 
one  fire  clay  and  is,  perhaps,  a  fair  sample  of  the  higher  grade  fire  clays  of  New  Jersey. 

No.  9  is  an  analysis  of  a  remark  iblv  refractory  fire  brick  of  the  Cornwall  or  Devonshire 
Kaolin.     Wagner's  Chem.  Tech.,  p.  321. 


23 


TABLE  "B  — NORTH  DAKOTA  FIRE  CLAYS. 


CONSTITUENTS. 


Silicon  (Si  O2  ) 

Aluminum  (AI2  O3  ) 

Iron  ( Fe2  O3  ) 

Calcium   (Ca  O) 

Magoesium  (Mg  O) 

Potassium  (K2  O) 

Sodium  (Na2  O) 

Water  and  volatile  matter 
Other  matter  and  errata. . . 


72.66 

17.33 

1.05 

0.13 


0.36 
0.38 
9.35 


B.y^ 


Q-g 


64.84 
24.31 
1.60 
0.11 
0.24 
Trace 
0.32 
8.58 


64.22 

17.22? 
2.09 

Trace 
0.37 
0.21 
0.34 

10.29 


50.45 
17.57 
2.80 
0.25 
1.79 
0.07 
0.86 
22.55 
3.66 


In  making  comparisons  of  the  analyses  of  the  clays  it  must  be 
remembered  that  in  all  cases  the  North  Dakota  clays  were  un- 
washed, and  in  most  cases  as  dug  from  surface  exposures.  By 
reference  to  the  tables  of  analyses  it  will  be  seen  that  sample  No. 
1  of  North  Dakota  clay  corresponds  quite  nearly  to  No.  1  of  the 
other  list  which  is  a  New  Jersey  clay,  extensively  used  for  a  fine 
fire  clay.  The  advantage,  however,  ajjpears  in  favor  of  the  North 
Dakota  clay,  since  it  contains  less  iron  and  alkalies.  It  also  seems 
superior  to  any  of  the  other  foreign  clays  of  list  "A,"  with  the 
possible  exception  of  No.  8.  North  Dakota  sample  No.  2  corre- 
sponds most  nearly  to  No.  2,  and  No.  9  of  table  "A,"  clays  from 
Dowlais,  South  Wales,  and  from  Devonshire  and  Cornwall,  Eng. 
The  North  Dakota  sample  again  appears  superior  on  account  of 
its  greater  freedom  from  iron  and  alkalies. 

Sample  No.  3  of  North  Dakota  clays,  though  probably  not  quite 
so  good  a  clay  as  Nos.  1  and  2,  is,  however,  of  fine  quality  and 
doubtless  superior  to  the  most  of  the  clays  in  table  "A." 

No.  4,  of  North  Dakota  clays,  that  from  Pembina  Mountains,  is 
probably  a  medium  grade  fire  clay.  It  appears  to  have  less  iron 
and  alkalies  than  several  of  the  foreign  clays  extensively  used  for 
refractory  purposes. 

When  we  consider  the  quality  of  the  clays,  the  ease  with  which 
they  can  be  mined,  the  abundance  of  the  clay  and  the  almost 
inexhaustible  supply  of  cheap  coal  near  the  most  of  it,  the  sur- 
rounding markets  and  the  means  of  transportation  at  hand  in 
most  cases,  there  seems  to  be  no  reason  why  these  clays  should 
not  become  the  basis  of  an  extensive  and  profitable  industry. 

Potter's  Clay. — The  term  potter's  clay  is  very  loosely  used  to 
designate  a  great  variety  of  plastic  clays.     For  convenience,  we 


24 


shall  in  this  article  make  but  two  divisions  of  potter's  clay,  viz., 
stoneware  and  earthenware  clays.  These  two  clays  are  those 
used  most  extensively  for  common  dishware;  the  stoneware 
being  the  poorer  quality  and  the  earthenware,  the  finer  white  dish- 
ware,  largely  used  for  tableware. 

Stoneware  Clays. — The  essential  requisites  of  this  class  of 
clays  are:  Plasticity,  fineness,  freedom  from  an  excess  of  impuri- 
ties such  as  iron  and  alkalies,  ability  to  stand  heat  well  and  to 
produce  a  strong,  impervious  body.  There  is  a  wide  variation  in 
stoneware  clays.  The  poorer  grades  are  but  a  little  better  than  a 
good  brick  clay,  while  the  finest  approach  very  close  to  earthen- 
ware clays.  The  typical  stoneware  clays  bake  to  a  strong,  sonor- 
ous and  sometimes  semi-vitrified  body.  They  are  usually  not  so 
fine  nor  so  homogeneous  as  the  earthenware  clays.  The  ware, 
after  baking,  is  opaque  and  commonly  of  a  gray  or  yellow  color, 
due  largely  to  the  presence  of  a  considerable  quantity  of  iron. 
The  coarser  stoneware  is  usually  salt-glazed,  but  the  finer  quality 
may  be  decorated  and  glazed  similar  to  earthenware.  Stoneware 
may  be  used  for  common  yellow  and  gray  ware,  for  jugs,  jars, 
plumber's  ware,  a  cheap  quality  of  dishware  and  for  many  other 
purposes. 

In  North  Dakota  there  are  several  localities  where  stoneware 
clay  is  found.  In  nearly  all  cases  the  material  is  from  fair  to  fine 
in  quality. 

!Near  Minot,  Ward  county*,  a  layer  of  clay  is  found  over 
the  coal,  which  is  apparently  well  adapted  to  the  manufacture 
of  stoneware.  The  clay  as  dug  is  of  a  bluish  gray  tint;  when  baked 
at  high  temperature  it  takes  a  creamy  tint.  It  is  very  fine  and 
has  a  greasy  feel.  On  baking  it  becomes  very  firm  and  hard,  and 
shows  but  little  tendency  to  crackle.  An  analysis  of  the  clay 
shows  the  following: 

Silicon  (Si  O2  ) 56.86 

Aluminum  (AI2  O3  ) 25.03 

Iron  oxide  (Fe2  O3  j 6.11 

Calcium  Oxide  (Ca  O) 0.71 

Magnesium  Oxide  (Mg  O) 0.76 

Potassium  Oxide  (K2  O) 0.50 

Sodium  Oxide  (Na2  O) 0.016 

Water  and  volatile  matter )  -iq  q-. ^^ 

Other  matter,  by  subtraction . . .  S 

In  the  Pembina  Mounfains,  near  Olga,  a  fine  white  clay  is  found 
which  would  doubtless  make  good  stoneware.  This  clay  is  found 
outcropping  along  the  bluff.  (I  repeat  the  description  given  on 
page  21.)  The  layers  which  have  been  seen  by  the  writer  were 
probably  not  of  sufficient  thickness  to  be  of  use;  but  from  the  re- 
ports of  others  there  seem  to  be  thicker  deposits.  An  illustra- 
tion may  be  seen  on  page  31  which  will  show  how  the  thinner 

♦This  clay  is  also  mentioned  on  p.  14. 


25 


layers  occur.  This  clay  is  very  white,  of  a  soapy  feel,  very  fine  in 
texture  and  is  acid  to  the  taste  and  to  litmus.  It  bakes  to  a  hard, 
strong  body  of  a  faint  pink  color.  The  acid  element  is  sulphuric 
and  may  in  part  occur  as  a  natural  alum.  By  washing,  this  clay 
would  probably  do  well  for  stoneware  and  for  several  other  pur- 
poses.    The  following  is  an  analysis  of  this  clay: 

Silicon  (Si02) 50.45 

Aluminum  (AI2  O3  ) 17.57 

Iron  (Fe2  O3  ) 2.80 

Calcium  (CaO) 0.25 

Magnesium  (Mg  O) 1 . 79 

Potassium  K2  O) 0.07 

Sodium  (Na2  O) 0.86 

Water  and  volatile  matter 22 .  55 

Other  matter  and  errata 3.66 

At  the  Plenty  Coal  Mine  in  Mercer  county,  a  clay  is  found 
associated  with  the  coal,  which  would  doubtless  make  an  excellent 
stoneware.  The  thickness  of  this  deposit  is  not  known.  This 
clay  is  very  much  like  the  Minot  clay  just  described.  Like  that, 
it  is  fine  in  texture  and  of  a  bluish  gray  color.  When  baked  in 
the  laboratory  furnace,  it  becomes  very  hard  and  strong,  and  takes 
a  creamy  tint.     An  analysis  shows  the  following: 

Silicon  (Si  O2   ) 60.79 

Aluminum  (AI2   O3  ) 16.2.3 

Iron   (Fe2  O3  ) 4.49 

Calcium  (Ca  O) 0.65 

Magnesium  (Mg  O) 1 . 02 

Potassium  (K2  O) 0. 19 

Sodium  (Na2  0) 0.28 

Water  and  volatile  matter,  by  subtraction 16.65 

About  Dickinson,  there  are  several  clays  which  will  make 
excellent  stoneware.  But  the  best  of  these  clays  are  too  good  to 
be  used  for  anything  but  the  highest  grade  white  stoneware, 
which  is  the  next  thing  to  earthenware.  These  clays  will  be 
described  under  earthenware  clays. 

For  the  purpose  of  comparison,  the  following  analyses  are  given 
of  clays  used  for  stoneware  in  various  localities  in  other  parts  of 
the  world. 

1. — *TJnglazed  stoneware,  Baltimore,  very  fine  white  body. 

Silicon 67.40 

Aluminum 29.00 

Iron 2.00 

Calcium 0.60 

Magnesium 

Potassium    }  ^  on 

Sodium        \ 0-60 

♦From  Muspratt. 


26 


2.  According  to  Salvetat,*  fine  yellow  wedgewood  ware  con- 
sists of: 

Silicon 66.49 

Alnminum 26.00 

Iron  oxide 6.12 

Calcium   1 .04 

Magnesium 0.15 

Alkalies 0.20 

3.  From  analyses  of  stoneware  by  the  same  as  No.  2,  the 
following  results  are  secured: 

Silicon from  62        to  75      per  cent. 

Aluminum from  19       to  29      per  cent. 

Iron  oxide from    1        to    8.5  per  cent. 

Calcium from    0.25  to    i      per  cent. 

Magnesium    from    0       to    0.9  per  cent. 

Alkalies from    0.50  to    1.5  per  cent. 

Most  of  the  stoneware  clays  of  New  Jersey  seem  to  be  of  superior 
purity,  especially  with  reference  to  iron.  By  comparing  the 
analyses  of  stoneware  clays  from  various  localities  with  those  of 
the  same  class  in  North  Dakota  it  will  be  seen  that,  as  far  as 
chemical  analyses  show,  the  clays  mentioned  from  this  state  are 
apparently  of  very  fair  quality. 

There  can  scarcely  be  any  doubt  but  what  these  clays  will  pro- 
duce an  article  fully  equal  to  the  average  of  this  class  of  ware. 

Earthenware  Clays. — The  purest,  finest  stoneware  clays  grade 
insensibly  into  earthenware  clays. 

Earthenware  clay  possesses  the  general  characteristics  of  fine 
stoneware  clay.  A  good  earthenware  clay  must  be  highly  plastic, 
very  free  from  iron  and  excess  of  alkalies,  and  must  bake  to  a 
strong,  compact  white  body.^;  Such  clay  is  the  material  used  for 
most  of  the  white  tableware.  The  comparative  rarity  of  this 
clay  and  the  large  number  of  uses  to  which  it  can  be  put,  on 
account  of  its  purity,  add  much  to  its  value. 

As  has  already  been  said,  clay  of  this  kind  is  found  in  England 
and  extensively  used  in  the  great  pottery  industry  of  that  country. 
In  the  United  States,  the  fine  clays  of  this  quality  form  the  basis 
of  the  great  pottery  industry  of  New  Jersey. 

In  North  Dakota  there  is  at  least  one  district  where  there  are 
large  deposits  of  clay  apparently  well  suited  to  the  manufacture  of 
earthenware.  These  clays  are  found  in  the  southwestern  part  of 
the  state,  in  the  vicinity  of  Dickinson,  Stark  connftj. 

These  deposits  have  already  been  mentioned  in  connection  with 
the  fire  clays.  The  description  of  some  of  these  will  be  repeated 
in  this  section.  The  clays  of  this  class  (white  earthenware  clays) 
found  about  Dickinson,  outcrop  near  the  top  of  high  bluffs.     In 

♦Beckwith's  "Pottery"  pamphlet.     P.  24 

JSee  the  general  remarks  under  Ctiaracteristics. 


Probably  loo  feet  or  more  in  height. 


CO 

(J 

Q 

< 

z 


^  '^ 

n'       !; 

^,  ^ 

V    d 

>    0^',/) 

E~  5) 

C  01   >. 

"C   0    « 

c  •«  n 
ra  aj  c 

P3  !0  a> 

u-a 


•5  2 


27 


some  cases  the  surface  soil  and  clay  seem  to  have  been  entirely 
washed  away  and  the  white  clay  is  left  capping  the  blutf.  Tliis  is 
the  case  with  a  deposit  of  very  fine  white  clay  about  a  mile  south 
of  Dickinson.  At  this  point  the  bluff  is  probably  100  feet  or  more 
high.  The  base  of  the  bluff  appears  to  be  chiefly  of  sand  and  clay. 
Above  this  is  a  very  deep  layer,  probably  from  10  to  15  feet  thick, 
of  fine,  white  earthenware  clay.  This  seems  to  be  covered  by  a 
layer,  perhaps  4  feet  thick,  of  very  pure  but  slightly  sandy  clay.  A 
cut  of  this  deposit  is  given  on  the  opposite  page. 

This  upper  clay  as  found  is  of  a  very  light  color,  but  bakes  still 
whiter.  It  produces  a  hard  body  showing  little  tendendency  to 
fuse.     An  analysis  of  this  clay,  as  dug,  is  as  follows: 

Silicon  (Si  02  ) 72.66 

Aluminum  (Al2  O3  ) 17.33 

Iron  (Fe2  O3  ) 1-05 

Calcium  (Ca  O) 0.13 

Magnesium  (Mg  O) 

Potassium  (K2  O) 0.36 

Sodium  (Na2  0) 0.38 

Water,  and  volatile  matter 9 .  35 

It  will  be  seen  from  the  analysis  that  this  is  a  very  pure  clay 
The  silicon  appears  rather  large  in  proportion  to  the  aluminum, 
but  this  is  due  to  the  presence  of  a  small  amount  of  sand  which,  if 
necessary,  could  be  removed  probably  with  very  little  trouble. 
The  iron,  it  will  be  noticed,  is  very  low  for  a  surface  specimen 
unwashed.  The  amount  of  alkalies  is  small.  Withal  this  clay 
would,  probably,  with  proper  treatment  make  excellent  earthenware 
material  suited  for  common  white  tableware,  etc.  The  clay  which 
it  has  been  said  is  found  immediately  under  this,  is  a  layer  perhaps 
from  10  to  15  feet  thick.     This  clay  is  very  fine  and  free  from  grit. 

It  can  be  dug  with  a  spade  and  the  lumps  can  be  powdered  in 
the  hand.  The  color  of  the  clay  as  dug  is  a  grayish  white, 
probably  due  to  a  slight  amount  of  carbonaceous  matter.  After 
baking,  it  is  pure  white.  It  has  a  very  fine  homogeneous  body. 
When  baked  it  becomes  very  hard  and  has  a  clear  sharp  ring.  It 
stands  heat  well  without  warping  or  cracking.  An  analysis  of  a 
sample  taken  from  a  surface  exposure,  and  as  dug,  gives: 

Silicon  (Si  O2  ) 64.84 

Aluminum  (AI2  O3  ) 24.31 

Iron  (Fe2  O3  ) 1 .60 

Calcium  (Ca  O) O-ll 

Magnesium  (Mg  O) 0.24 

Potassium  (K2  O) Trace 

Sodium  (Na2  O) 0.32 

Water  and  volatile  matter,  etc.  by  subtraction 8.58 

This  analysis  shows  a  very  pure  clay  and  one  which,  when 
washed  and  purified,  seems  well  proportioned  for  the  potter's  use. 
The  fluxing  constituents  and  the  iron  are  not  high  f(jr  an  un- 
washed surface  specimen.     This  clay  has  been  formed  into  small 


28 

dishes  and  baked  at  high  temperature  in  the  laboratory.  The 
bisque  came  out  a  very  fine,  white,  compact  body.  It  had  a  good 
ring  and  showed  no  tendency  to  crackle  or  warp. 

A  sample  of  clay  which  had  been  cleaned  and  mixed  and  tem- 
pered ready  to  be  formed,  just  as  used,  was  taken  from  one  of  the 
large  Trenton  potteries  and  analyzed  with  the  following  results: 

Silicon  (Si  O2  ) 69.03 

Aluminum  (AI2  O3  ) 2.3.89 

Iron  Oxide  {Fe2  O3  ) 0.45 

Calcium  Oxide  (Ca  O) 0.29 

Magnesium  Oxide  (Mg  O) 0.05 

Water  and  volatile  matter 7 .  46 

Potassium  (K2  O)  ^                                                                           ^ 
Sodium  (Na2  O)     ) 

By  comparing  this  analysis  with  the  last  mentioned  from  North 
Dakota,  it  will  be  seen  that  there  is,  in  some  respects,  a  consider- 
able similarity  in  composition.  The  North  Dakota  clay  is  a  little 
higher  in  iron,  but  it  must  be  remembered  that  the  sample  from 
the  Trenton  pottery  had  been  washed  and  thoroughly  prepared 
for  ware,  while  the  sample  from  North  Dakota  was  just  as  dug. 
There  is  but  little  doubt  that  this  clay  is  well  suited  for  white 
table  ware  and  the  like  uses.  The  supply  of  the  clay  is  evidently 
abundant.  The  surroundings  are  all  that  could  be  asked.  At  the 
foot  of  the  bluff  where  the  clay  is  found,  there  is  a  small  stream 
which  would  furnish  water  for  the  factory.  The  deposit  is 
probabl)'^  not  more  than  a  mile  and  a  half  from  the  main  line  of  the 
Northern  Pacific  railway.  So  a  spur  track  could  be  easily  run  to 
the  deposit.  Coal  is  found  in  great  abundance  and  is  mined 
within  a  few  miles  and  can  be  gotten  at  a  very  low  price.  There 
is  plenty  of  material  for  saggars  in  which  to  bake  the  ware. 

There  are  doubtless  other  good  earthenware  clays  in  this  vicin- 
ity although  the  writer  has  not  visited  any  such  deposits.  How- 
ever, samples  of  one  or  two  other  fair  clays  have  been  received 
and  analyzed.  The  analysis  of  a  sample  from  about  Dickinson, 
furnished  by  Mr.  E.  F.  Messersmith  gave  the  following  results: 

Silicon  (Si  O2  )  64.22 

Aluminum  (AI2  O3  ) 17.22  (?) 

Iron  (Fe2  O3  ) 2.09 

Calcium  (Ca  O) Trace 

Magnesium  (Mg  O) 0.37 

Potassium  (K2  O) 0.21 

■Sodium  (Nao  O) 0..34 

Water  and  volatile  matter 10 .  29 

Good  earthenware  clays  may  be  discovered  in  other  parts  of  the 
State;  but  no  such  deposits  are  known  to  the  writer.  For  the  pur- 
pose of  comparison,  analyses  are  given  of  a  number  of  earthenware 
clays  found  in  different  parts  of  the  world,  and  extensively  used 
for  the  manufacture  of  whiteware,  etc. : 


29 


>• 

s^ 

■e 

"«« 

ic 

c 

"  J! 

■  -  5 

•O  0 

so. 

a 
It 

0)  _'C 

-  J3 

CONSTITUENTS. 

i> 

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a    - 
c  — 

l-J 

u.!2 

u 

1 

7. 

1 

r^ 

11 

5U 

0 

1 

*"* 

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•  «  il 

t^ 

o 

o 

o 

o 

°5^ 

6  iU 

o 

z 

IZ 

z 

Z 

^ 

Z 

Z 

45.45 

38.75 

1.15 

43.40 

37.56 

1.04 

69.03 

23.89 

0.45 

0.29 

66.20 

24.11 

0.79 

46.38 

38.04 

1.04 

1.20 

I 

35.65 

32.50 

1.65 

Trace. 

66.60 

28.00 

0.70 

0.30 

Magnesium 

0.11 

0.05 

Trace 

) 

0.60 

0  17 

0  35 

0.96 

1 

1 
J 

L 

3.40 

0.37 
15  40 

■■ 

30.05 

Water  and  Volatile  Matter 

13  05 

7  48 

7  20 

13  44 

Other  Matter.                 

1.32 

1.40 

0.20 

3SS      0.15 

Nos.  1  and  2.     From  New  Jersey  Chiv  Report  of  1878. 

No.  3.  From  analysis  made  of  clay  from  a  Trenton  pottery,  mixed  and  proportioned  ready  for 
use. 

No.  4.  From  Williams'  Applied  Geology. 

No.  5.  Muspratt  gives  this  analysis,  by  Mr.  Higg-inbotham,  of  clay  used  in  Staffordshire  pot- 
teries. 

No.  6.  From  Muspratt,  Cornish -stone  clay,  so  extensively  used  in  fine  white  ware  and  China 
clay,  in  the  impure  state. 

No.  7.  From  Muspratt;  Laurent,  analyst.     (Supposed  to  be  from  the  ware,  not  the  clay.) 

Hydraulic  Cement  Clay. — Besides  the  several  kinds  of  clay 
that  have  already  been  mentioned  as  found  in  different  parts  of 
North  Dakota,  there  is  found,  also,  in  at  least  one  locality,  natural 
hydraulic  cement  clay.  The  writer  has  not  had  the  time  or  means 
to  make  a  very  careful  investigation  of  this  subject,  so  it  will  not 
be  possible  to  speak  as  fully  or  as  definitely  as  would  be  de- 
sirable, regarding  this  deposit.  It  is  hoped,  however,  that 
enough  may  be  said  to  interest  some  to  investigate  the  formation 
further. 

Hydraulic  cement,  also  known  as  water  lime  cement,  hydraulic 
lime,  etc.,  is  usually  understood  to  mean  a  mixture  of  lime  and 
clay  which,  after  burning,  will  form  a  mortar  or  cement  capable 
of  hardening  and  retaining  and  increasing  its  hardness  under 
water.  Such  a  cement  is  either  natural  or  is  prepared  artificially 
by  burning  a  proper  mixture  of  certain  rich  limestone  and  a  suit- 
able clay, 

A  widespread  and  growing  demand  for  hydraulic  cement  and 
the  fact  that  first-class  natural  cement  deposits  are  not  widely 
distributed,  have  led  to  a  considerable  manufacture  of  artificial  ce- 
ment. When,  however,  a  good  natural  cement  can  be  found,  it  is 
likely  to  be  first  sought. 


30 


There  are  many  varieties  of  cements  varying  in  character  and 
value  in  different  localities,  and  even  in  the  same  deposit.  The 
two  most  distinctly  different  kinds  are  those  that  set  slowly  but 
eventually  become  very  hard,  and  those  that  set  rapidly  but  never 
become  so  firm  and  hard  as  the  slow  setting  kind.  The  first 
variety  is  best  where  great  strength  is  required  to  sustain  enor- 
mous pressure.  The  second  variety  is  better  where  it  is  necessary 
that  the  mortar  should  harden  immediately  but  where  the  pres- 
sure is  not  so  great. 

Hydraulic  cements  of  different  kinds  are  used  extensively  for 
cisterns  and  wells,  sewers,  bridges,  lighthouses,  walls,  foundations 
of  heavy  buildings,  cellar  floors,  sidewalk  paving,  manufacture  of 
artificial  stone,  etc. 

The  difference  in  behavior  between  common  and  hydraulic  lime 
may,  perhaps,  be  in  part  accounted  for  in  the  following  way. 
"  Common  lime  is  burned  from  carbonate  of  lime  or  carbonate 
of  lime  and  magnesia  as  nearly  pure  as  can  be  obtained;  and  the 
hardening  of  the  mortar  made  from  it  is  due  in  part  to  the  re- 
formation of  lime  carbonate,  in  part  to  the  crystalization  of  hy- 
drate of  lime  upon  the  grains  of  sand  and  probably  in  part  to  the 
slow  formation,  during  ages,  of  lime  silicate,  in  virtue  of  which  a 
good  mortar  grows  harder  with  age.  Hydraulic  lime,  on  the  other 
hand,  is  burned  from  limestones  notably  impure,  containing,  as 
analyses  show,  from  twenty  to  about  fifty  per  cent,  of  silica,  alumina 
and  iron  oxide;  it  either  does  not  slack  at  all  with  water  or  slacks 
very  slowly  and  with  great  difficulty,  needing  therefore  to  be  ground 
to  a  fine  powder  before  being  used;  and  its  hardening  in  mortar  is 
due  to  a  chemical  combination  of  lime,  or  lime  and  magnesia,  with 
silica  and  alumina  partially  effected  during  the  burning,  and  par- 
tially by  the  agency  of  water,  forming  hydrated  silicates  and 
aluminates  of  lime  and  magnesia,  which  are  insoluble  in  water." 

Hydraulic  limes  are  found  in  a  number  of  localities  in  Europe 
and  are  extensively  used.  In  the  United  States,  there  are,  fortun- 
ately, several  regions  containing  deposits  of  natural  hydraulic 
lime,  found  at  different  horizons. 

"The  lowest  of  these  horizons  is  in  the  calciferous  group,  which 
at  Utica,  in  La  Salle  county.  111.,  and  at  several  points  in  Maryland 
and  Virginia,  furnishes  hydraulic  limes  of  satisfactory  quality,  and 
may  be  expected  to  do  the  same  at  points  on  the  same  range  in  east- 
ern Pennsylvania.  The  water-lime  group,  at  the  base  of  the 
lower  Helderberg,  with  some  kindred  limestones  belonging  just 
beneath  it  in  the  geological  series,  furnishes  nearly  ninety  per 
cent,  of  all  the  hydraulic  lime  and  cement  produced  in  the  United 
States,  being  largely  burned  in  Ulster  county.  New  York,  furnish- 
ing the  esteemed  Kosendale  cement,  also  in  Oneida,  Madison, 
Onondaga,  and  Erie  counties,  and  near  Sandusky,  in  Ohio;  while 
the  well-known  Louisville  cement  is  obtained  according  to  Prof. 
James  Hall,  from  beds  of   the  Corniferous  period  belonging  just 


31 


above  this  in  tlie  geological  series.  A  limited  outcrop  of  rocks  of 
the  Hamilton  period  at  Milwaukee,  Wis.,  furnishes  the  Milwaukee 
cement.  The  St.  Louis  limestone,  of  the  sub-carboniferous,  is  said 
to  give  promise  of  hydraulic  properties  at  several  points  in  Illinois 
while  impure  limestones  of  the  coal-measures  furnish  "Parker's 
cement,"  in  Belmont  county,  Ohio,  and  the  "  Johnston  cement,"  in 
Cambria  county,  Pa.* 

In  North  Dakota,  a  natural  hydraulic  cement  clay  is  found  in 
what  is  known  as  the  Pembina  Mountain  district.  This  clay,  as 
well  as  the  shales  of  the  district,  probably  belongs  to  the  upper 
Cretaceous  period. 

About  twelve  or  fourteen  miles  north  of  Milton,  Cavalier 
county,  near  Olga,  an  outcrop  of  hydraulic  clay  is  found.  This 
outcrop  occurs  in  a  deep  ravine  making  into  the  valley  of  the 
Pembina  river.  This  deposit  of  calcareous  clay  is  probably  about 
350  or  400  feet  below  the  level  of  the  surrounding  prairie  and 
within  a  few  feet  of  the  bed  of  a  small  creek.  The  clay  appears 
to  form  a  small  ridge  or  hogback  near  the  foot  of  the  bluff.  This 
ridge,  which  is  quite  free  from  trees,  shrubs  and  grass,  which 
cover  so  thickly  most  of  the  hillside,  has  been  so  washed  as  to 
show  something  of  the  lower  formation  of  that  part  of  the  valley. 
The  following  figure  may  give  some  idea  of  the  occurrence  of  this 
deposit.  The  position,  nature  and  thickness  of  the  layers  marked 
in  the  figure  are  only  approximately  correct. 


Fig.  1  is  a  section  showing;  the  side  of  a  vallev.  The  Top,  "a,"  is  about  400  feet  above  the  bot- 
tom, "c,"  where  there  is  a  small  creek.  And  "b"  is  the  ridge  from  which  the  hydraulic  clay  appears. 

Fig.  2  is  a  section  of  the  knob  "  b  "  of  figure  1. 

In  figure  2,  "  A  "  is  about  5  ft.  of  soil  and  shale. 

"  B"  is  about  30  ft.  of  black  carboniferous  clay,  impregnated  slightly  with  sulphur  and  alum. 

"C"  is  about  2  to  3  ft.  of  very  fine  white  clay,  of  slightly  acid  taste.  (Stoneware  and  probably 
medium  grade  fire  clay.) 

"  D"  is  about  30  or  40  ft.  of  black  clav.     "  E  "  is  about  3  to  6  ft.  ( ?)  of  hydraulic  cement  clay. 

♦Williams'  Applied  Geology,  p.  99. 


32 


It  is  impossible  at  present  to  state  what  is  the  extent  of  this 
layer  of  cement  clay,  but  there  seems  to  be  no  reason  why  it 
should  not  prove  extensive.  The  clay  can  be  easily  picked  out  in 
lumps,  which  are  sufficiently  firm  to  bear  handling,  but  which 
split  into  thinner  layers  that  can  be  rubbed  to  a  fine  powder  in 
the  hand.  The  clay  is  of  a  leaden  gray  color  and  very  homoge- 
neous. Occasionally,  where  splitting  occurs,  there  may  be  seen 
impressions  of  small  shells,  but  the  softness  of  the  material 
makes  it  difficult  to  preserve  these  forms  perfect.  This  clay 
seems  to  be  Cretaceous  and  probably  is  in  the  lower  portion  of 
those  beds  which  Warren  Uphara  regards  as  of  the  Fort  Pierre 
subdivision.* 

The  writer  has  analyzed  this  clay  and  has  also  given  it  an  actual 
test  by  burning  it  to  hydraulic  lime  and  then  using  it  underwater. 
The  burning  gave  a  rather  quick  setting  cement.  It  forms,  ap- 
parently, a  very  strong  and  hard  body.  No  tests  were  made  for 
tensile  or  crushing  strength.  A  sample  of  the  clay  was  sent  to 
one  of  the  eastern  cement  factories  for  examination,  the  report  of 
which  examination  gave  a  good  hydraulic  cement.  The  fact  of  its 
being  so  easily  mined  and  prepared  would  much  lessen  the  expense  of 
production.  This  advantage  will  be  appreciated  when  it  is  under- 
stood that  much,  if  not  most,  of  the  natural  cements  of  many  lo- 
calities is  in  rock  form,  which  requires  an  extra  expenditure  to 
mine  and  crush.  An  analysis  of  this  clay  before  calcination  gave 
the  following: 

Silicon  (  Si  O2  ) 18-52 

Aluminum  Oxide  (  AI2  O3  ) 5.36 

Iron  Oxide  (  Fe2  O3  ) ^4.08 

Calcium,  calculated  as  Ca  CO3 70.64 

Magnesium,  calculated  as  Mg  CO3    0.76 

This  analysis  shows  a  material  very  much  like  the_  Kufstein 
natural  hydraulic  lime,  of  Kufstein,  Germany,  which  is  said  to 
produce  an  excellent  cement.  The  composition  of  the  Kufstein 
marl  is  as  follows  :J 

Silicon 15-92 

Aluminum 5.94 

Iron  Oxide J^'^^ 

Calcium  Carbonate 70-64 

Magnesium  Carbonate 1  -  f^2 

Gvpsum  0-34 

Potash 0-55 

Soda 0.82 

Water  and  organic  substances 0-/9 

*  "This  reference  has  been  confirmed   during- the  field  work   of   1886  bv   the   discovery  in   the 
shale  in  this  locality  and  in  its  continuation  southward  on  the  head  streams  of  Park  river,  of  Scaph- 
ites  Nicolletti  (Morton),  Scaphites  Nodosus    (Owen),  Baculites  Ovatus  (Say),  and  Baculiles  Com- 
nressus  (Sav);  two  species  of  Inocerainus,  one  of  which  is  I.  Altus  (Meek)." 
*^  [From  Warren  Upham  on  "  Upper  Beaches  of  Lake  Agassiz. 

JWagner's  Chem.  Tech. 


33 


It  is  hoped  that  what  has  been  said  on  this  subject  will  lead  to 
further  observation  and  research  regarding  this  formation.  If 
this  hydraulic  material  can  be  shown  to  exist  in  abundance  and 
not  too  far  from  the  railroad,  there  seems  to  be  no  reason  why  it 
should  not  become  the  source  of  a  flourishing  industry. 

Conclusion. — From  what  has  been  said  it  may  justly  be  con- 
cluded that  North  Dakota  is  richly  supplied  with  a  variety 
of  valuable  clays.  The  excellent  brick  clays  which  are  so  widely 
distributed  throughout  the  state  are  sure,  as  the  country  develops 
and  the  cities  and  towns  increase  in  size  and  number,  to  become 
very  important  factors  in  growth,  in  substantiality  and  in  beauty. 

Sooner  or  later  the  superior  brick  clays  of  several  localities  are 
likely  to  become  known  and  appreciated  and  their  products  sought 
by  cities  of  neighboring  states.  Growth  and  improvement  in  the 
cities  will  also  tend  toward  developing  the  clays  fitted  for  sewer 
and  drain  pipes,  for  various  sanitary  and  other  purposes. 

There  seems  no  reason  why  those  districts  supplied  with  good 
fire  clay  may  not  soon  become  centers  of  a  lively  industry  in  man- 
ufacturing fire  brick  and  other  refractory  material. 

There  are  some  excellent  stoneware  and  probably  good  white 
earthen-ware  clays.  The  constant  demand  for  articles  of  these  wares 
may  be  expected  to  result  in  establishing  factories  for  their  pro- 
duction. If  the  deposits  of  hydraulic  cement  clay  prove  to  be  ex- 
tensive, they  may  be  used  largely,  as  the  source  of  water  lime. 

There  is  little  room  to  doubt  that  in  course  of  time  the  clays  of 
North  Dakota  will  become  the  source  of  industries  that  will  play 
no  small  part  in  the  general  development  and  growth  of  the  com- 
monwealth. 

The  importance  of  the  clay  industry  in  several  foreign  countries 
is  somewhat  known,  but  few  who  have  not  investigated  the  sub- 
ject, realize  the  magnitude  of  this  business.  Several  years  ago,  in 
one  of  the  shires  of  England,  in  Staffordshire  alone,  it  is  said  that 
over  100,000  operatives  were  employed  in  connection  with  the  clay 
industry.  Likewise  in  Germany  and  France,  in  China  and  Japan, 
this  is  an  industry  of  great  importance.  In  the  United  States,  in 
those  of  the  older  states  that  possess  rich  deposits  of  clay,  there 
has  already  sprung  up  a  flourishing  business  in  the  manufacture 
of  a  variety  of  clay  wares.  This  is  especially  noticeable  in  New 
Jersey  and  Ohio.  The  total  value  of  the  articles  manufactured 
from  clay  annually,  in  the  United  States,  is  probably  from 
$65,000,000  to  $90,000,000  or  more. 

North  Dakota  possesses  at  least  two  advantages,  viz.,  location  and 
fuel  suj)ply,  which  would  aid  greatly  in  successfully  establishing 
a  large  clay  industry  in  the  state.  Its  situation  is  such,  with  ref- 
erence to  deposits  of  fine  clays  in  other  localities  that  it  would 
naturally  have  a  large  supporting  territory.  The  use  of  the  coal 
found  in  such  abundance  in  the  close  proximity  to  the  finer  clays, 


34 


would  doubtless  be  a  great  help  in  keeping  down  the  cost  of  manu- 
facture. 

The  advantage  to  the  state  would  be  those  always  secured  by 
the  introduction  of  manufacturies  into  an  agricultural  community. 
New  industries  develop  resources  before  unused,  keep  at  home  as 
well  as  bring  in  a  large  amount  of  wealth,  enlarge  the  demand  for 
other  products,  foster  other  industries,  and  in  many  ways  add  to 
the  general  prosperity. 

Although  the  results  of  these  investigations  are  encouraging,  it 
is  not  expected  that  a  great  industry  of  this  kind  will  be  at  once 
established.  That  requires  time.  It  is  hoped,  however,  that  the 
value  of  these  clay  resources  will  be  appreciated,  and  that  event- 
ually the  clays  of  the  state  will  be  extensively  used.  To  this  end 
it  is  hoped  that  these  investigations  may  be  helpful. 

E.  J.  Babcock, 
Department  of  Chemistry  and  Geology, 

State  University,  Grand  Forks,  N.  D. 


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INDEX. 

Page. 
Aanlyses  of — 

Fire  Clays  from  Various  Localities 10 

Porcelain  and  Earthenware  Clays  from  Various  Localities 12 

North  Dakota  Brick  Clays 14 

Tile,  Drain  and  Sewer  Pipe  Clays  from  Various  Localities 18* 

Tile,  Drain  and  Sewer  Pipe  Clays  of  North  Dakota 19 

Fire  Clays  from  Various  Localities 22 

Fire  Clays  from  North  Dakota,  and  Comparisons 23 

Stoneware  Clays  of  Various  Localities,  and  Comparisons 25,26 

Earthenware  Clays  of  Various  Localities,  and  Comparisons 2& 

Hydraulic  Marl  (foreign) 32 

Hydraulic  Marl  of  North  Dakota 32 

North  Dakota  Clays,  Table  of 35 

Brick  Clays — 

Origin  and  Distribution 4 

Characteristics  and  Composition 7 

In  North  Dakota 13 

Characteristics  and  Composition  of  Clays 6-12 

Cement  Clay  (hydraulic) 29-32 

In  North  Dakota 31, 32 

Drain  and  Sewer  Pipe  Clays,  etc.,  in  North  Dakota 14-17 

Earthenware  Clays- 
Origin  and  Distribution 5 

Character  and  Composition 10, 11 

In  North  Dakota 26-28 

Fire  Clays- 
Origin  and  Distribution & 

Character  and  Composition 8 

In  North  Dakota 19-23 

Geology  of  North  Dakota  Clays  (summary) 6 

Hydraulic  Cement  Clay.     (See  Cement  Clays.) 

Local  Descriptions 13-35 

Object  of  the  Report 4 

Origin  and  Distribution 4 

Potters'  Clay — 

Signification  of  the  Term 5 

Origin  and  Distribution 5 

In  North  Dakota 23 

Stoneware  Clays  in  North  Dakota 24, 25 

Tables  of  Analyses.    (See  Analyses.) 


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